2001 Tacoma - RPM Bounce When Letting Off Gas

I have a 2001 Tacoma Double Cab (3.4L) with an automatic transmission and about 170K miles. When I am driving over 50mph and then let off the gas, the RPMs will lower as expected. However, maybe a second later, the rpms will then drop another 200-300 rpms and then rise back to expected. Here is a link to a video showing the issue: https://youtu.be/2R2Ka94VyFo

It does not do this all the time, but is pretty consistent if the engine rpms are over 2K. For example, if I put the truck in 2nd gear going 30 mph and give it gas and then let off, it will experience the issue. If I have the truck in overdrive going 50+ mph and let off the gas, it will experience the issue.

Any advice on what might be going on here? Is this a torque converter issue? To rule out a few things, I replaced spark plugs, replaced the TPS, cleaned the MAF, throttle body and IAC. Transmission fluid looks good and is filled properly. Still have the problem.

 

You ever figure out what it was? Idk if you’re still out there. Worth a try tho!