What does
rclone backend features myserver:
Print?
According to the code
// Precision shows whether modified time is supported or not depending on the
// FTP server capabilities, namely whether FTP server:
// - accepts the MDTM command to get file time (fGetTime)
// or supports MLSD returning precise file time in the list (fLstTime)
// - accepts the MFMT command to set file time (fSetTime)
// or non-standard form of the MDTM command (fSetTime, too)
// used by VsFtpd for the same purpose (WritingMDTM)
So the server has to support precise modtime listing as well as setting.
Can you run
rclone touch myserver:Files/test.txt -vv --dump bodies
and post the output from that?