Imagine a situation: we have an incoming channel and most of the funds are on our side, let's say remote peer only has reserve + commit fee left (minimal amount to sustain a channel) and then we send an outgoing HTLC which will increase commit tx size and accordingly a commit tx fee.

Since remote peer is the funder they are to handle an updated commit tx fees, but here: https://github.com/ACINQ/eclair/blob/master/eclair-core/src/main/scala/fr/acinq/eclair/channel/Commitments.scala#L149-L153 we do not check for that. This may get such a channel force-closed by remote peer with low local balance.