Pretty much as the title states; HP16500 + 16510 State/Timing card, in state mode. The analyzer complained about the clock being slow or missing, so I connected it to one of the input channels (same pod) and it sees it as always high. I checked with a scope and the clock is there, there's a bit of ringing but it might be caused by the way I was probing it, either way the device that uses that clock runs without issues.
The clock signal in question is a 4MHz clock being generated from an ATTiny85 with TMR0 in CTC mode (internal oscillator set at 16MHz and divided by the timer to 4MHz); I did this because I didn't have an oscillator module of the right frequency and the device under test doesn't have the ability to output a clock when run from its internal oscillator.