I've just posted three new open problems:

1. Cross-composition product of binary relations is a quasi-cartesian function
2. Cross-composition product of pointfree funcoids is a quasi-cartesian function
3. Cross-composition product of reloids is a quasi-cartesian function

I interlinked these three problems each with two others. But I see only one related problem in the section "Related problems" of the problem description. It seems that it is a bug.