Version Information

Fabric version: 0.12.1 + API 0.41.3
Botania version: 420-FABRIC-SNAPSHOT (commit ad3fa1b)

PS: Only legit crafted lens get consumed, but not lens from /give and REI

Looks like having a full inventory is an actually important step for this? I seem to be getting weird behavior with the lens items when removing them, so this is probably a client-server desync and you don't actually have a lens there.

Seems to be related to making lenses stackable.

that's what I worried about, when getting a stack of lenses, they work, but not individual lenses

I have trouble reproducing this exact effect, I have done a small adjustment that makes lenses behave slightly better in creative (ceaf735), but I have doubts it will change anything.

I see you are using some other mods. Can you provide a game log file and the modpack/modlist?
Can you try narrowing down the modlist (eg. through binary search) to possibly identify the culprit yourself?

Log file doesn't say nothing I should be aware of at the time I apply a lens on a spreader.
This is my modlist

I will try binary search in a few minutes

also, from my testings the lens only apply if they're part of a stack (more than one lens in the same stack, as soon as the stack drops to 1, lens don't apply anymore and instantly vanish)

PS: https://streamable.com/nph85z

UPDATE: I tested with ONLY Botania (and trinkets + patchouli as dependencies) and I reproduced it. they work in creative because they don't get consumed.

https://streamable.com/jqsb7x

Cannot reproduce. Please try on current commit anyways.

will do.

Gonna close the issue. Thanks for taking your time to sort this out.

Looking at the commits, I'm not sure what got changed that could affect the lenses, but they are working now. Commit b9ac1e9