Yes, Amazon Sponsored Display campaigns can re-enter the learning phase even with small edits, especially when targeting smaller or more niche audiences. While Amazon doesn’t publish a strict threshold, certain actions commonly trigger the reset—like changing audience segments, adjusting creative elements (images, headlines), modifying bids significantly, or tweaking optimization goals. Even frequent pauses and restarts can have an impact.
What’s likely happening in your case is that one audience is more sensitive—possibly due to lower volume or fewer conversions—so the system has to relearn after each change. Even if the campaigns look identical, small differences in audience behavior or data history can cause one to re-optimize more aggressively.
To reduce this, try grouping edits together and avoid tweaking the campaign daily. Let it stabilize for a few days between changes so the algorithm has time to gather consistent data.
If you share what kind of edits you're making, I can help you figure out which ones are safest to adjust without triggering learning mode again.