Not sure if it depends on your mod, but when I update to a version higher than 1.2.15 the following message appears on game start:

Error loading mods
Failed to load mods: Error while running setup for entity prototype "burner-assembling-machine" (assembling-machine): When next_upgrade is set entity mining result must not contain item product with "hidden" flag set. Mining results with no item products are allowed.

Mods to be disabled:
- lignumis (1.0.57)
- atan-ash (2.2.1)

Wrote this here because of these mods weren't updated recently and the crash appears with a newer remembrance version
Will post the error messages on the lignumis and atan-ash mod as well

Got an answer in the Lignumis forum:

[quote="cackling.fiend "]Was atan-ash added recently? I'm not sure if it's really that mod as I don't see any code that does it (I only had a quick look).

I currently don't support "Exotic Space Age: Remembrance" because compatibility code is on the other side. Maybe ask there.[/quote]

Got an answer in the Lignumis forum:

cakling.fiend:
Was atan-ash added recently? I'm not sure if it's really that mod as I don't see any code that does it (I only had a quick look).
I currently don't support "Exotic Space Age: Remembrance" because compatibility code is on the other side. Maybe ask there.

Related to merging items. Fix in 1.2.20.

Thanks for the fix! And the great mod!