Machine # 1 - Asus Prime Z390A, i7-9700k 3.6GHz, 32.0 GB ram, Tumbleweed 64-bit, KDE Plasma 5.24.0
Machine # 2 - Asus P8Z77-V Deluxe, i7-3770k 3.5GHz, 16.0 GB ram, Tumbleweed KDE Plasma 5.24.0

Not sure if Dolphin is the problem, just starting here to solve problem.

In moving files [using Dolphin] from HDD to USB stick it sometimes takes up to 15 minutes to move/copy a file.
Most files that are moved are between 500MiB to 2.GB large.
The progress bar in the 'moving' display window shows 'finished' [sometimes in seconds] but the window does not say 'finished' for up to 15 minutes.

When I finally receive the msg that the file has finished being moved/copied and I go to "Safely Remove" the USB stick again I might have to wait for upto 10 -15 minutes before the stick can be removed.

This is only happening with some files [no particular file types or USB brands]

Has anyone encountered this problem?
What can be done to correct it?
Thank You