The bug fixed in libp2p/go-libp2p-secio#44 is causing problems with the new write coalescing patches. To reproduce:

• Build the latest go-ipfs master.
• Build go-ipfs 0.4.20.

Connect them and try to pin. This will fail.

To verify that this is really the issue, you can upgrade secio in 0.4.20 and only secio and the bug magically goes away.

Unfortunately... I think the only solution is to disable write coalescing for a release or two until the network upgrades.