Why didn't my target go up this session?

Usually it's the weight you were expecting to move, and that's working as intended. BulkForged uses double progression: each exercise has a rep range, and you climb it a rep at a time before the weight goes up. The weight only moves once your lowest working set reaches the top of the range — then reps reset to the bottom and you climb again. Until then the rep target is what advances, by one rep above your lowest set each session.

If nothing at all moved, the usual reason is that one more rep than your lowest set landed exactly on the target you already had — you came a single rep short, so the target waits for you there. That's a hold, not a miss: reps inside your range are never treated as a failure. One set under your previous target also holds it, since a single off set is not evidence of anything. If two sets came in under it, the target eases down to meet you rather than leaving you chasing a number you can't hit today.

There are a few other reasons a target sits still, and none of them means you did anything wrong:

You were on a deload week, or tapped the Light day chip. Deliberately light sessions are invisible to the engine on purpose — the target freezes through the week and picks up exactly where it left off. Training light when you planned to is the session working, not a session wasted.
No working set counted. If the exercise wasn't logged, the sets weren't marked complete, or they were logged far below your working weight, the engine reads the exercise as skipped and leaves the target alone for next time.
The session was logged somewhere else. Targets are kept per routine, so a Quick Workout, a Record Attempt, or the same lift logged on a different training day won't move this routine's target.

A genuine stall — the same weight and reps for two or more sessions in a row — is worth a closer look at recovery, or a deload; a single in-range session that didn't reach the top is just normal progress in motion.