I have not yet been able to determine the conditions under which this happens but I have been experiencing inconsistent behavior when casting 104 and 105.

INCANT 104
You gesture while calling upon the lesser spirits to aid you with the Disease Resistance spell...
Your spell is ready.
You gesture.
Your spell misfires.
Cast Roundtime 3 Seconds.

The solution to resolving the issue seems to be to STOP the spell then recast it.

>stop 104
With a moment's concentration, you terminate the Disease Resistance spell.
You lose your extra internal fortitude.
>incant 104
You gesture while calling upon the lesser spirits to aid you with the Disease Resistance spell...
Your spell is ready.
You gesture.
There is a dim flash around you.
You feel a strengthening of your internal fortitude.
Cast Roundtime 3 Seconds.

>incant 104
You gesture while calling upon the lesser spirits to aid you with the Disease Resistance spell...
Your spell is ready.
You gesture.
There is a dim flash around you.
You feel a strengthening of your internal fortitude.
Cast Roundtime 3 Seconds.
>

-- Robert

Interesting idea but nope, all my own spells.

-- Robert