Conversely, folders without special characters are treated normally.
Note that this happens on all folders having special characters, which means around 12,000 photos are affected. Needless to say, I am not interested in doing a massive synchronization at this stage because of this problem.
I recently imported my catalogue from Lightroom 6 to Lightroom Classic CC.
My photos are stored on a Synology NAS and mounted as SMB remote folders.