As often as not, that's a result of shit infrastructure behind the Skype for Business deployment itself, rather than the client itself. There are a number of baffling restrictions baked into the server and protocol itself, and a real production-grade deployment is a byzantine mess that would give Cthulu nightmares.

It doesn't help that the client hasn't had much more than cosmetic changes in at least five years, and is largely abandoned for Microsoft's kludgey Slack competitor.

I use it daily and we never had issues with it.

When something bad happens, usually it is network infrastructure related or some IT experiment going on.