PDM keeps changing my parts to read only

I have an assembly open and I have it checked out and saved.

I open a part within that assembly and check it out, make changes and save.

go back to my assembly and it changes to read only.

click on PDM vault blueberry and right click on top assembly and the check out option is greyed out.

all other options will replace the part I just made the changes to

SW 2018 SP5.0

SolidworksSolidworks Pdm/enterprise Pdm