Issue #23452: [USSEP] Female merchant clothes - gaps in arms when worn
Someone reported this on Nexus Mods: link
Screenshot from that report: https://i.imgur.com/Q2TXLoE.jpg
I was able to confirm this in my game as well, so it's a legitimate issue that probably has something to do with the USLEEP to USSEP conversion. Hana thought that possibly the meshes just need to be reconverted.
The most relevant thing from the tracker that touched these is Issue #12099.
By the way, there isn't an issue with the male version of the meshes from everything I can tell.