Claim Button On Defense Wouldn't Work

[RavenousPartyLibrarian]

Today I farmed T4 defense for quite a while, looking for Loki systems. On wave 35 I got it, and I went to click claim & exit to farm on the next part. It didn't work. After uncannily clicking it over and over again, trying some buttons like escape and whatever else I could think of, the timer ran out and I got killed. Mission failed, no Loki prime systems for me.

 

I'm a bit upset of course, but if this isn't a bug and just something else that'd be nice. Making this either way just in case.