As you have indicated that you were experiencing an issue with realtime reporting in your Classic Analytics property. Our Product and Engineering team has extensively investigated this issue to find the root cause, but after making a few improvements to the report we have not been able to fully eliminate the issue.
Knowing that this issue is temporary and that ‘Google Analytics 4’ (GA4) properties have an improved Realtime report that does not suffer from this issue, we’re no longer seeking to resolve this issue. We recommend waiting a few minutes to see accurate numbers in UA Realtime reports, or we invite you to consider implementing an GA4 property alongside your existing Universal Analytics property to access our next generation of Real-time reporting (help center: https://support.google.com/analytics/answer/9744165?hl=en&ref_topic=9143232).
We understand that this may be frustrating to hear after so many months of waiting, but please know that we exhausted all options before coming to this conclusion. Unfortunately we will not be able to help troubleshoot the Realtime inflation/deflation further.