After taking a shower I noticed water under tub in crawlspace.

After discovery, I dried ground and started testing but cant make the same puddle to occur again (of course!):
Ran tub thru spout only. No visible leak in crawlspace.
Ran shower thru head with nobody in it, no visible leak in crawlspace.
Caulk appears in good shape and there was no overflow or significant water on floor after shower.
Viewed drainpipes while running water and saw no moisture. Also did not see any moisture on the hot/cold copper pipes( no visible leak/puddle with shower off)
When shower/tub in off position, after 4 hours I see no visible puddle and only moisture where water exited/accumulated from behind wall and out a small hole that phone wiring exits.

Heres where I am confusing myself. When I found the puddle underneath, the only difference from any other time I shower was the diverter was left in the shower position overnight where normally it stays in the tub position. Perhaps unreleated, the valve/cartridge has leaked for a year into the tub from spout (I think I need new seats/springs) I wonder if the leaking cartridge with the diverter left in the shower position overnight caused the leak?

Unfortunetly a closer look at joint at head or the valve requires cutting of tile from front or drywall from back.

Any ideas or suggestion you can lend (besides call a plumber) ?