383DA Clip not releasing

Last week, I took my Bersa 383DA to the range to tests some hand loads. I noticed that the magazine did not release when I pressed the magazine release after the last shot. This happened every time. If I had I rounds in the clip, it works fine. Unfortunately, I only had one of my two clips with me. I thought I had a bad clip. I brought the gun home and on a hope, removed the grips, sprayed some cleaner inside the handle and wiped it out. Today I took both clips out to the range and got the following results:
The clip I thought was bad is number 1 and the clip I thought was good is number 2.

Loaded clip 1 and fired five shots, pressed the release and the clip dropped about half an inch.

Loaded clip 2 and fired five shots, pressed the release and the clip failed to release.

Loaded clip 1 and fired five shots, pressed the release and the clip failed to release.

Loaded clip 2 and fired five shots, pressed the release and the clip dropped about half an inch.

Loaded clip 1 and fired five shots, pressed the release and the clip failed to release.

Both clips failed, but not consistently. I did notice when the clip failed to release, the slide catch was still between
the slide catch and the hammer, maybe a eighth inch or so from the notch for the catch. Move the slide back, push
the slide catch up, press the release and the clip will drop the half inch. The notch for the catch has crisp edges and does not appear to be round out.

During this process, I never had a failure to feed, fire, or eject. Even the last round ejected flawlessly.

The previous week, I was using reloads... ten each of the following:
3.6, 3.7, 3.8, 3.9 grains of Winchester 231 with a 95 grain Remington round nose with the lead base exposed.
Today, I was using store bought PMC Bronze, 90 gr FMJ.

I think the clips are good. It has been in the safe, untouched for six years or more. Prior to that, everything worked flawlessly, so I am hoping it only needs to be taken apart and deep cleaned, maybe a spring or something replaced.

Any ideas from the group would be appreciated...

Thanks in advance

Frank