collection of stuff/glitches i did:
why did pebble's stamina overcap
i got sand to the water :)
i ran out of stamina at one depth (not a glitch guess how i did it)
I haven't seen that glitch before, but my guess is that the Titanium Pickaxe might be triggering its free dig at the same time Pebble collects a restore cell and gains +1 max stamina. I'll need to test it myself to figure out what's going on. Thanks for reporting!
Edit: Should be fixed now.
You unequip and re-equip your pickaxe over and over again.