Look for dishwasher and sink area leaks.
I don't have dishwasher
Where do you have these kitchen tiles? On the counter? BAcksplash?
OK and there was NO water in the bucket?
Where are they applied?
I would guess plumbing leak and would pull one off and look at what’s going on.
the liquid appears in different places and times,sometimes is black and sometimes clear
here is a recent photo after nobody was in kitchen ,just was like that in the a.m.
I am afraid to pull up any tiles because a friend did that and ended up with having men in spacesuits doing the rest of removal,a real mess.
Water will settle in lowest spots so that may be why you are seeing water in different places? Sounds strange, I would get it checked out by a professional.
Could be a leak in one of the waste lines since it does not happen all the time. A pressured line leak would be ongoing.
Look beyond where you see the water instead think about what is water nearby. It can travel undetected under the flooring to the low spot where you are seeing it.