Tabs reloading is the stock browser bug. It is related to OOM only marginally, in the sense that by not caching the open tabs, they are trying to reduce the RAM usage to reduce the chance of OOM. If the real OOM kicked in, the whole browser would be killed, not just some tabs needed reloading.

I agree it is annoying as hell especially if you are entering some data in the tab that gets reloaded. I am sure Stskeeps et al would call it a feature but I call it unquestionably a bug. No other mobile device I have ever used does that, not even this cheap and underpowered Android tablet I am using right now.