After installing the sync, there shouldn't be any files in the "presets" folder anymore, I believe. Yours should be in "private presets"
In order for people to see the updated version of your preset, THEY have to restart their FH, not you. This is because every time one starts up their FH, the preset sync goes through and adds (or deletes) any new/changed files into their "public presets" folder. So since the other people didn't restart, nothing in their "public presets" folder has updated yet
Yet, I do believe the sync is slow at updating replaced files, so in the meantime you could manually give files to those you want to see the correct preset