**System Information**{F10328605}
Operating system: macOS-10.15.7-x86_64-i386-64bit 64 Bits
Graphics card: AMD Radeon Pro Vega 64 OpenGL Engine ATI Technologies Inc. 4.1 ATI-3.10.18
**Blender Version**
Broken: version: 2.93.3, branch: master, commit date: 2021-08-17 18:30, hash: `rB8b80d19f3641`
Worked: Don't know
**Short description of error**
I imported the alembic from T90806 in an empty scene. Added a light. It renders in Cycles with motion blur. If I import a second version of the same alembic, or duplicate it, sometimes I lose MB on all of them or sometimes some of them.
**Exact steps for others to reproduce the error**
I wanted to send some blend file bit they are too big. Also, I wonder why that happens has the alembic is a cached file so it shouldn't take any space in the blend file but for every copies of the alembic I import in my file, the blend file gets and extra 10 megs. So to reproduce, just importe multiple copies of the abc file or duplicate it. Turn on MB of course.
This bug report is derived from T90806