autodiff gave very low-difficulty job
I see in the logs that a very low difficulty job was given.  Is this some bug in the autodiff code?  Here is the information I have:

XMRig logs:
```
[2022-07-04 14:33:43.827]  miner    speed 10s/60s/15m 8050.2 8120.2 7997.2 H/s max 8257.1 H/s
[2022-07-04 14:33:44.037]  cpu      accepted (1524/0) diff 256385 (0 ms)
[2022-07-04 14:33:44.416]  net      new job from 23.124.76.211:3333 diff 252140 algo rx/0 height 2659999 (173 tx)
[2022-07-04 14:33:52.446]  net      new job from 23.124.76.211:3333 diff 252140 algo rx/0 height 2659999 (173 tx)
[2022-07-04 14:33:54.005]  net      new job from 23.124.76.211:3333 diff 252140 algo rx/0 height 2659999 (168 tx)
[2022-07-04 14:33:58.572]  net      new job from 23.124.76.211:3333 diff 252140 algo rx/0 height 2659999 (168 tx)
[2022-07-04 14:34:04.019]  net      new job from 23.124.76.211:3333 diff 252140 algo rx/0 height 2659999 (172 tx)
[2022-07-04 14:34:07.546]  cpu      accepted (1525/0) diff 252140 (1 ms)
[2022-07-04 14:34:14.413]  net      new job from 23.124.76.211:3333 diff 1000 algo rx/0 height 2659999 (172 tx)
[2022-07-04 14:34:14.598]  cpu      accepted (1526/0) diff 1000 (1 ms)
[2022-07-04 14:34:14.640]  cpu      accepted (1527/0) diff 1000 (0 ms)
...
...
[2022-07-04 14:34:25.402]  cpu      accepted (1597/0) diff 1000 (1 ms)
[2022-07-04 14:34:25.466]  cpu      accepted (1598/0) diff 1000 (1 ms)
[2022-07-04 14:34:25.484]  net      new job from 23.124.76.211:3333 diff 192005 algo rx/0 height 2660000 (45 tx)
[2022-07-04 14:34:33.817]  net      new job from 23.124.76.211:3333 diff 192005 algo rx/0 height 2660000 (47 tx)
[2022-07-04 14:34:38.787]  net      new job from 23.124.76.211:3333 diff 192005 algo rx/0 height 2660000 (47 tx)
[2022-07-04 14:34:39.153]  net      new job from 23.124.76.211:3333 diff 192005 algo rx/0 height 2660001 (1 tx)
[2022-07-04 14:34:40.152]  net      new job from 23.124.76.211:3333 diff 192005 algo rx/0 height 2660001 (1 tx)
[2022-07-04 14:34:43.874]  miner    speed 10s/60s/15m 8049.4 8117.7 8005.5 H/s max 8257.1 H/s
[2022-07-04 14:34:50.014]  net      new job from 23.124.76.211:3333 diff 192005 algo rx/0 height 2660001 (2 tx)
[2022-07-04 14:34:52.232]  cpu      accepted (1599/0) diff 192005 (1 ms)
```

P2Pool logs:
```
p2pool-p2pool      | 2022-07-04 14:34:04.0219 BlockTemplate final reward = 0.619559621973 XMR, weight = 300302, outputs = 70, 171 of 198 transactions included
p2pool-p2pool      | 2022-07-04 14:34:04.0223 StratumServer sent new job to 1/1 clients
p2pool-p2pool      | 2022-07-04 14:34:14.4074 SideChain add_block: height = 2545299, id = bf9a7ca71cd25a3c37b38026754323c96868d5408bb491eadc0305692aba8a13, mainchain height = 2659999, verified = 0
p2pool-p2pool      | 2022-07-04 14:34:14.4110 SideChain verified block at height = 2545299, depth = 0, id = bf9a7ca71cd25a3c37b38026754323c96868d5408bb491eadc0305692aba8a13, mainchain height = 2659999
p2pool-p2pool      | 2022-07-04 14:34:14.4121 SideChain new chain tip: next height = 2545300, next difficulty = 1389040180, main chain height = 2659999
p2pool-p2pool      | 2022-07-04 14:34:14.4122 BlockTemplate base  reward = 0.600000000000 XMR, 200 transactions, fees = 0.019795370000 XMR, weight = 356340
p2pool-p2pool      | 2022-07-04 14:34:14.4159 BlockTemplate final reward = 0.619559637973 XMR, weight = 300298, outputs = 70, 171 of 200 transactions included
p2pool-p2pool      | 2022-07-04 14:34:14.4161 StratumServer sent new job to 1/1 clients
p2pool-p2pool      | 2022-07-04 14:34:16.7347 SideChain add_block: height = 2545300, id = ba5435af34dbb339051a5eecc25dd980211739c905961c9b5088af48cb0e8205, mainchain height = 2659999, verified = 0
p2pool-p2pool      | 2022-07-04 14:34:16.7367 SideChain verified block at height = 2545300, depth = 0, id = ba5435af34dbb339051a5eecc25dd980211739c905961c9b5088af48cb0e8205, mainchain height = 2659999
p2pool-p2pool      | 2022-07-04 14:34:16.7375 SideChain new chain tip: next height = 2545301, next difficulty = 1388345261, main chain height = 2659999
p2pool-p2pool      | 2022-07-04 14:34:16.7376 BlockTemplate base  reward = 0.600000000000 XMR, 200 transactions, fees = 0.019795370000 XMR, weight = 356340
p2pool-p2pool      | 2022-07-04 14:34:16.7389 BlockTemplate final reward = 0.619559637973 XMR, weight = 300298, outputs = 70, 171 of 200 transactions included
p2pool-p2pool      | 2022-07-04 14:34:16.7391 StratumServer sent new job to 1/1 clients
p2pool-p2pool      | 2022-07-04 14:34:25.4736 P2Pool new miner data
p2pool-p2pool      | ---------------------------------------------------------------------------------------------------------------
p2pool-p2pool      | major_version           = 14
p2pool-p2pool      | height                  = 2660000
p2pool-p2pool      | prev_id                 = a6c5bc25d536f9d9cae7b9335abbf80b382cf21a9e2f5061dbf54ea4eaad9de8
p2pool-p2pool      | seed_hash               = 9cfa17830fb15f710e8ddc5d6ebcd340deb857fc33cf2d6950ff4613b034ff2d
p2pool-p2pool      | difficulty              = 320187164098
p2pool-p2pool      | median_weight           = 300000
p2pool-p2pool      | already_generated_coins = 18143197978043650606
p2pool-p2pool      | transactions            = 46
p2pool-p2pool      | ---------------------------------------------------------------------------------------------------------------
p2pool-p2pool      | 2022-07-04 14:34:25.4737 BlockTemplate base  reward = 0.600000000000 XMR, 44 transactions, fees = 0.001242230000 XMR, weight = 70178
p2pool-p2pool      | 2022-07-04 14:34:25.4739 P2Pool new main chain block: height = 2659999, id = a6c5bc25d536f9d9cae7b9335abbf80b382cf21a9e2f5061dbf54ea4eaad9de8, timestamp = 1656945148, reward = 0.618615510000 XMR
p2pool-p2pool      | 2022-07-04 14:34:25.4872 BlockTemplate final reward = 0.601242230000 XMR, weight = 72914, outputs = 70, 44 of 44 transactions included
p2pool-p2pool      | 2022-07-04 14:34:25.4874 StratumServer sent new job to 1/1 clients
p2pool-p2pool      | 2022-07-04 14:34:33.8108 SideChain add_block: height = 2545301, id = 9d902ec224bf724a0b2e7223158552a61da8973309c042f87827bf3c53005598, mainchain height = 2660000, verified = 0
```