OK.. forgive me if these were answered.. but I would trouble shoot this as follows:

1. in DIFFERENT algos, is your midi clock reliable/stable?

2. When you hook your midi clock up to a monitor ( i rec MIDI OX on PC).. do you see any unexpected values?

3. have you tried a different clock source?

4. Can your clock source send a CC tap?

I would stress #2. SO MANY problems are from MIDI source, and without an objective view of what is actually being sent you are wasting your life.