@c4pp4 , sorry for late reply.
it is actually interesting - could be that my assumption about WIFI is not exactly valid.
I tried MS Edge (browser) and DuckDuckGo (browser) and both made my phone crashing when I had WIFI enabled - but in both cases it loaded page normally (which I had open from previous session) and only scrolling up/down page content made my device crashing.
After that I also tried HERE WeGo Maps and I downloaded some map content having only WIFI enabled and it seem to be ok.
when I try mentioned browsers without WIFI again, all works well..