Several questions have been migrated to m.se of late, and several others have been put "on hold" as off-topic, and I'm having trouble seeing how the distinction is made between the two courses of action. For example, both https://mathoverflow.net/questions/135342/find-the-eigenvectors and https://mathoverflow.net/questions/135314/equivalent-condition-for-certain-an-equation have been put on hold, where it seems to me that both should just be migrated to m.se. Maybe people who are voting to close as off-topic aren't following the prompts that would lead them to suggest migration?
There is a broad consensus among most active users on MSE that questions should satisfy certain minimum quality standards. See for example this meta thread there. While MSE welcomes questions on all levels of mathematics, there are still standards on how questions there should be asked. They should tell the background of the problem, what the asker has tried themself etc. It is a sad fact that many questions pass on MSE that violate these standards, but I would appreaciate if MO users would not make the situation worse.
When in doubt, only transfer questions which would be good questions on MO if they would be on a more advanced level.