Yes, this is quite true for any servers that are running 1.7.10 minecraft. Please note that there's a message that broadcasts this information as well as the /rules hold a tip that lets you extend your absence via /absence command. This will allow the claim to stay for up to a month. Sorry, seems I replied without checking what modpack this question lies under. I don't think that this issue is something to do with how islands work.
It is project ozone. I really don't want to lose my island. My computers motherboard is screwed up. I ordered a new hoping it will be in but it's not.
I have been notified that protection will be lifted after certain time however island is still available no matter what.
All you will loose is the quest progress which gets deleted after an inactivity of 1 week. This is needed to keep the server playable as the hqm mod does not work nicely with the amount of players the server has.
I would also suggest if you can get in the server to take everything you have on your character and put it into a chest. Unless things changed, when going away for an extended amount of time, while you keep your island, you could lose the stuff on your character due to purging player data.
