While experimenting with a relay chain testnet, Decentration and I ran into this issue with multiple validators on the same node, stalled finality and got the chain into slow block-making mode.
We tried to restart finality with api.tx.grandpa.noteStalled and then managed to stall block production completely with this error, trying and failing to build the next block once a minute or so:
🙌 Starting consensus session on top of parent 0xdf1c27f8e8c9210f224b6849cead0e9ab257f73b78444007c746ae8c42cf5410 🎁 Prepared block for proposing at 24410 (6 ms) [hash: 0xcddfad6034e4e777627004e33da3fdb98ef3c0787182f1aefe6677f83be8726c; parent_hash: 0xdf1c…5410; extrinsics (2): [0xca0f…d245, 0x15a4…b00e]] 🔖 Pre-sealed block for proposal at 24410. Hash now 0x9dd9e87a0d6e77516f656eee094897f0ad64ef1cf4d0a62269ba617f0340d99b, previously 0xcddfad6034e4e777627004e33da3fdb98ef3c0787182f1aefe6677f83be8726c. 👶 New epoch 72 launching at block 0x9dd9…d99b (block slot 274112089 >= start slot 274112018). 👶 Next epoch starts at slot 274112618 Not applying authority set change forced at block #24405, due to pending standard change at block #23434 Error with block built on 0xdf1c27f8e8c9210f224b6849cead0e9ab257f73b78444007c746ae8c42cf5410: ClientImport("A pending forced authority set change could not be applied since it must be applied after the pending standard change at #23434") 💤 Idle (11 peers), best: #24409 (0xdf1c…5410), finalized #23324 (0x4169…831c), ⬇ 0.9kiB/s ⬆ 1.4kiB/s
Was this the right method but we got the parameters wrong, or should we have used something else?