Why was the previous version for this anime with 25,000 members removed?

As mentioned previously, they changed it to a different one to keep the DB clean.

As mentioned previously, they changed it to a different one to keep the DB clean.

There is no update on the project for 3+ years now.
It's likely cancelled , so MAL deleted the entry to keep the database clean.

Seems like a mods did not liked that idea , and brought it back...

That's a very rare case.

You can find many projects that got cancelled without any warning , with only the original announcement saved somewhere on internet.
3 years in development without any communication on it , strongly hint toward a cancellation , or at the very least to a problematic production.

Anyway , my point was not to question if it's cancelled or not , but that MAL deleted the entry because they believed so.

I'm sure u realize that's an extremely rare case

They also removed the "Orbital Era" movie from the database, which was announced by Otomo at the same time as this new Akira adaptation.
Ironically, while there's no sign of life for Shin Akira, Otomo last year said that Orbital Era is still in production: https://twitter.com/otomo_zenshu/status/1557346412165091328