It appears that the two bottom nails that make the hanger connection to the ledger are missing. It’s not right, but to me would not be a big deal with a big increased chance of failure. In fact I would consider it to have a very small effect on the chances of joist-to-ledger failure if that’s the only problem. In two solid years of rolling joists in CA, I left out the same bottom two nails, and never got called on it.
I would forget right away all those calculations unless you are a licensed structural engineer, and in that case you wouldn’t be asking about this on the message boards.
If many joists have a gap where they met the ledger, that’s indicates a potential problem. Fasteners installed toward the end of the board are more likely to fail if some force tends to pull the joists further from the ledger. It’s not the resjlt of two missing hanger nails.
If the joists were originally butting the ledger as they should have been, then this condition indicates a problem that should should be identified and corrected before it causes widespread failure.