Hello BI,
Pretty much explains itself. Whenever the launcher is opened, it seemingly decides that all Workshop mods need to be updated. There are no steps to reproduce as I know right now.
I have seen people complain about this issue on the Reddit as well, saying that it's a problem with running Arma on a separate drive, but that can't be true because it happens even when only one drive is set up with the OS.
Attached is the most recent launcher export.