Open alpha testing of the 5.0 HD mod (online lobby).

The saves became different in different patches, simultaneous turn is glitching, heroes are duplicated as if the same hero is both receiving and giving a stack.

Different in what way?
The save format hasn't changed since 5.0 beta 1 from August 19, 2017, for SoD.
And since 5.0 beta 23 from December 28, 2017, for HotA.
This is a fact.

How exactly is the simultaneous turn glitching? (It also hasn't changed much in the last few months.)

Heroes are duplicated as if the same hero is both receiving and giving a stack.

Where and how does this happen? How can this be reproduced? Is the conclusion based on one specific case, or has this happened repeatedly?

A panicked post with confusing information, zero details, and specifics won't help find and fix problems, if they exist.

After the release of RC16, the following bugs were identified and very quickly fixed (by RC20):
1. HP not regenerating after a quick restart,
2. Critical hit in the mine, garrison, and when joining creatures with all slots occupied.
3. Inability to open the market window and other buildings in the city.
4. Issues with the spacebar key in the city.
5. Crash in the external market and external artifact trader.

Does anyone have any complaints about RC20 now? What are they?