Mask flag -m in the //move command deletes all other blocks

Server Implementation

Paper

Server Version

1.21

Describe the bug

When selecting a region and executing //move 1 up -m [block], the masked [block] is moved while all others are deleted. Any vector yields the same result.
Using normal world edit, doing the same command moves the masked [block] while keeping all others intact.

To Reproduce

1. Select a region with more than one block type.
2. Execute: //move 1 down -m [block] with a chosen block and any vector
3. Behold the mass destruction. My god, what have you done...

Expected behaviour

The masked block(s) are moved and all others should remain. This is not the case with this issue.

Screenshots / Videos

Error log (if applicable)

No response

Fawe Debugpaste

https://athion.net/ISPaster/paste/view/ad57abf54a794c9aaba70851c2529209

Fawe Version

FastAsyncWorldEdit 2.11.3 SNAPSHOT 930

Checklist

• I have included a Fawe debugpaste.
• I am using the newest build from https://ci.athion.net/job/FastAsyncWorldEdit/ and the issue still persists.

Anything else?

No response

Start by reproducing the issue with a mixed-block selection and the //move 1 down -m [block] command, using the linked FAWE debugpaste for context. Trace the //move mask-handling path and compare it with normal WorldEdit behavior; done means masked blocks move while unmasked blocks remain intact for arbitrary vectors.