Messages went entirely missing; not even local echo

[ara4n]

Steps to reproduce

1. Sent two msgs into a room while on good data
2. Both vanished entirely; no local echo

Outcome

What did you expect?

never ever drop msgs

What happened instead?

msgs were sent, and subsequently turned up later (after a ss timeline reset or something)? but at the time both local and remote echoes didn’t happen at all

Your phone model

No response

Operating system version

No response

Application version

834

Homeserver

No response

Will you send logs?

Yes

[bnjbvr]

Likely another instance of matrix-org/matrix-rust-sdk#3941: there's a small time window (after a local echo has been sent, but before it's been remote-echoed in sync) where messages will temporarily disappear. It's independent of the event cache storage, but might depend on both the connection speed (not the case, as noted in OP) and the processing speed of the homeserver.