My skins take about 5 days to save. Every time I log in to a server I have a new present, and it is always the same as I have been getting for the past week or so. It switches every once and a while(5 days), but I have only gotten common or classy items so far. I don't know if this counts as a bug or not. It is really annoying so I hope it is resolved soon.
Also, when I get a new skin it doesn't show up in my collection until a day or two later. I am running on the latest version on Linux Mint.
The caves problem is just that I have to disconnect and reconnect every time I enter/leave a cave or my game crashes.
I just run Linux Mint and play on Dedicated Servers.