In FE8, if you use this hack and have a unit join at the max level cap it glitches out.
This solution only works for a flat level cap, as in the max level is the same for every class.
For instance, a flat cap of level 30.
Go to $17EA8 and replace 14 with whatever hex your cap is.
In the case of 30, I'd change 14 to 1E.