I mapped my Akai Midimix to control certain parameters of the Digitakt but if I move any knobs/sliders too quickly or too many at one time theres a glitch/audio drop out.
Make sure that you’ve not created a MIDI loop.
Other than that I have no idea, except maybe the Akai controller sending more MIDI over USB than a MIDI DIN connection can handle. But if they’re both connected via USB, this shouldn’t matter.
I can send tons of MIDI messages to the Digitakt and have never experienced any glitches or dropouts. And that’s a lot more MIDI than any single controller should generate with two hands at the controls.