Yes, I just noticed this myself yesterday...
The issue is related with the new AISv3 inventory fetch feature. I already have a workaround for it, but will try to find the root cause and fix it instead.
The good news is that, in the mean time, you do not need to relog when such a thing happens: simply temporarily (or permanently, if you do not care about inventory thumbnails) disable the "Network" -> "Use AISv3 for inventory fetches" option (this will also instantly make any missing items appear in your inventory).
EDIT: here is the patch for the workaround, for people building the viewer themselves from sources: