An illuminated manuscript of Macrobius which visited Melbourne a few years ago has “Cum in Africam venissem M Manilio consule.”
So consul is in the ablative and it makes sense to take it as an ablative absolute. ie - “with M Manilius as consul” or “in the consulship of M Manilius”.
But the Loeb and so many examples on the net have it as “cum in Africam venissem M Manilio consuli” which makes consul look like it’s in the dative.
If it’s in the dative I have no idea how the grammar works.
Consul is not an i-stem so there doesn’t appear to be a good reason for the “i”.
Is it just a typo that’s spreading like the plague?