If a fuel injector bypasses internally, with no fuel for the combution stroke, can the piston going down with both valves closed, expecting detonation, create enough suction to pull the valves open thereby allowing the pushrod cap to have enough slack to fall off?

We had a pushrod cap come off and found that the injector was not popping but instead bypassing internally. Should I be looking for another cause of the pushrod cap to come off?