I plan to set commercial flooring tile in a closet (so the aesthetics are secondary) and have 1/2" plywood over 3/4" OSB for substrate. Now, as you can see in the picture, the plywood wasn't perfectly cut to retrofit the somewhat irregular shape of the closet and has gaps about as wide as a carpenter pencil at the widest.
[[ Picture pending ]]
Should I try to fill the gaps with something like a square dowel + wood glue + wood filler or will it be fine to leave it like this. I don't expect anyone to be walking around these edges in the closet so I don't anticipate heavy load exposure.