Rat pee issues :(

Today I noticed some liquid seeping though the bottom of one of the rat hammocks. A shooed out the girls and found that it in fact was pee and there were also a few poops too. I took out this bed too wash and both rats have been using the litter box since then and both rats were are very active and playful this morning, so Im not worried that one might have a UTI or anything like that. I really think my rats would rather just pee in bed then move the foot or so to the litter box! So, I guess I'll try moving this bed really close to the litter box?

Has anyone else had an issue like this? My rats are 90% litter box trained (one of them doesnt get it as well as the other...). Rodents aren't supposed to eat or sleep where they go to the bathroom, but clearly my rats arent bothered... any advice?