Have you tried changing the outputs to Gates rather than Triggers (default)?
Trig / Gate output
By default, Grids produces trigger signals (short 1ms pulses). This behavior - which is recommended for 808 or 909-like sound modules - can be changed in order to produce gate signals more suitable for controlling envelopes or other modules’ CV inputs. In this case, the output stays high for the whole duration of the clock’s positive cycle. It is thus possible to alter the gate length by driving Grids from a clock module with a duty cycle parameter (or from a square VCO with pulse-width control). The internal clock has a fixed 50% duty cycle. To change the trig/gate configuration, turn C2 (MAP Y).
LEDs off: Outputs are triggers.
LEDs on: Outputs are gates.