It looks like the issue with automatic int=>float conversion that previously existed on trashbin with >2 GiB data inside (of was it >2 GiB individual file size) now happens in the files app as well.
Also desktop client sync is affected for the same reason.
64-bit support was formally dropped due to the trashbin error, and also e.g. that >2 GiB couldn’t be downloaded via web interface on 32-bit systems, but those issues were acceptable for many 32-bit system users, including me. But the core functionality broken now is a real problem.
It wasn’t really clever to do this change while allowing 32-bit clients to upgrade without warning. A wave of broken instances (which hopefully have a backup or find this workaround for the time being) and related reports can be expected. EDIT: Was no intention, culprit seems to be a removed workaround in 3rdparty sabre submodule: Remove 4GB file size workaround for 32bit OS / Stream Videos on IOS by schoetju · Pull Request #184 · sabre-io/http · GitHub