with a good scanner you know you’re getting precise and accurate readings. You’re not having any shifting error so it lets me know your solenoid pack (temp sensor and major valve body component) isn’t bad.
Here’s a troubleshooting list:
1. Take for the 8 pin connector on driver side of trans and unplug/inspect.
2. Inspect harness by the exhaust and bellhousing, could definitely be intermittent due to a melt or frayed wite
3. Check grounds, not just trans area
Are you having any other issues that could help pinpoint the issue??