It might be that the saddle wood and top wood have expanded/contracted to different degrees, causing the top wood to split along the grain. String tension may have contributed, but all guitars have string tension so that’s not really the cause.
If it has been stored in a particularly cold or hot place, or worse at place with significant temperature and/or ...
I think there are two possibilities, and from the photos and the info I don't know which one is most likely.
There was some defect in construction, and the tension of the strings is gradually pulling the bridge out.
Due to a one-time event (fall, blow, major temperature change event, etc.) a crack appeared, but it's not going to get worse.
I've seen both. ...
If it was mine I'd be concerned. I'd check the woodwork under the bridge (inside the soundhole), and if it was flat, I'd glue a piece of wood - maybe ply- under that section, a good inch bigger all round. With epoxy resin, and well clamped. If that meant drilling the holes through after, for the pegs, so be it. All that may not mend the cracks, but they ...
Please provide more information on posts like this. No one can really tell what's going on. Is the crack in the top near the bridge, or a separation of the bridge from the top.
Based on the limited information there are a few things it could be.
If the top is cracked through the wood then the integrity of structure is compromised and (1) could split more ...
Changing strings on a floating trem bridge requires never changing gauge, and changing stings fully one by one, not taking them all off. It's pretty limiting if you want to deviate then you will have to go through all these steps:
blocking the trem
changing strings one by one
adjusting trem counter pressure