Severe Temporary Shrinking After Several Hours of Chastity Wear and Some Pinching

Hi all. Something quite strange occurred for me a few days back. While wearing my cage, late in the evening I began to feel an odd pinching sensation near the base of my cock. It felt as though the joint connecting the two parts of my Holy Trainer (v3 standard) was catching on something (I had this problem with a cheap CB before), yet the Holy Trainer has never done that previously and is usually very smooth, so I was puzzled. I ran my finger over the spot to locate the culprit but couldn’t find anything obvious. The pinching lasted only briefly, really just one or two seconds each time, occurring maybe four or five times total. It didn’t frighten me much; I assumed it was merely some chafing. However, later that evening when I took off my cage to play with my girlfriend, I noticed my erection looked significantly smaller than normal. I recall being 16cm (just over six inches), so I grabbed a ruler and found it had shrunk to 12cm (just under five inches). Also, the base of my cock where the pinching happened felt harder than the rest. At first this seemed hot because I am into some sph dynamics, but then concern set in. I became quite soft and discussed it with my girlfriend over the phone since we are long distance. Soon after, arousal returned, and within seconds my cock expanded back to its usual size, or close enough—about 15cm (just under six inches). I distinctly remember it being at 16 before. This morning it remains at 15; I’m unsure if this relates to the incident, if I was perhaps a bit too generous in measurements previously, or if it has just changed gradually over time. Regardless, I am uncertain about what happened and honestly feel somewhat anxious. It doesn’t seem like the “shrinking” that affects some individuals during extended chastity play. I have been wearing this cage 24/7 for roughly two weeks now; I spent another full week in it previously as well. Two nights before the incident, I was allowed out of the cage for a ruined orgasm and my cock appeared perfectly fine then. So I strongly feel the shrinking is connected to that pinching sensation. Since then, I haven’t slept with the cage on because I fear the pinching might happen again during sleep without waking me, potentially causing more serious issues. Does anyone have any thoughts on what this could be?