I noticed this problem when I experimented with a 'master-clock' idea.
Using the CV bit, I tried both the PO-12 and my ancient SoundMaster SR-88 to supply the clock.
Both ran the microsequencer fine, but very short gate.
Yesterday, with my new inverter & latch, I had a go at building the 8-step Sequencer layout and noticed if one removes the trigger connection to the envelope the same short gate suddenly appears.
Today, at some point, I'm going to try taking a clock from the PO-12 into CV bit to tigger the sequencer then take a trigger from he sequencer to the envelope and see what happens...