1. You said
The newest team member is using a SHORTCUT on the OneDrive Desktop to open the FE in the stated folder.
The shortcut can be anywhere since it isn't active once the launch of the targeted file/app occurs. Nothing else happens to the shortcut. If I remember this correctly, the shortcut is treated as though it was a one-line command line equivalent to "RUN X with parameter Y". So running via a shortcut is SIMILAR to running from a batch script... a very SHORT batch script. (Could be wrong - but I think that is correct.) The shortcut's properties and content are not altered, so even if OneDrive was involved, it would have no updates to make to the cloud copy.
The crucial aspect is where the targeted app resides. In theory, since the implied launch occurs on the user's PC, the launched code - the FE in this case - will have to have a clear, unobstructed path (in the network sense) to the PC and its memory. If you can't put a shortcut on the desktop but CAN have a user's files on that machine in a local folder, don't make the shortcut a desktop shortcut, but instead make it just an icon in the user's home folder. (Technically, a desktop shortcut is just another file in the implied folder that is the desktop.) Open Windows Explorer (or whatever they are calling it these days) to the user's working folder and launch from there.
2. You asked
For them, the FE is installed on a network (\\networkname\username\) folder that only the individual user has access to. Could this be part of the issue?
As long as each user's FE resides in a folder where a different user won't try to open it, you should be OK.
The thing you want to avoid is that two users will open the same physical file. (Not talking about users opening COPIIES of the same file.) When two users open the same file simultaneously, you have locking issues AND you have the potential for the file's contents to get scrambled. That is why we tell you to copy the FE and only share the BE file.
3. You asked about using CTRL/C and CTRL/V as copy/paste to move bulk data from one place to another.
If you have any tabular forms (similar to datasheet view) where a group of controls could be copied at once, I suppose it is possible to get all bollixed up with a bulk copy/paste. People used to Excel-like behavior have some bad habits to break and that is one of them. But for that to happen, you have to have a grid-like form in two places where a copy-from and a paste-to can occur. I would think you would know whether you had such a thing.
Let me digress for just a moment. In Excel, you have the explicit ability to select multiple cells and do a CTRL/C copy, then move to another sheet or segment thereof and do a CTRL/V paste. When you do that, though, Excel asks you whether you wanted to jam everything into a single cell or do a paste maintaining separation of cells or do some other type of paste. It also matters whether you select enough cells in the desitnation area to hold the cells you selected from the copy area. In any case, you get options.
When you do that grid-oriented copy/paste with Access, you don't get options because Access treats grids differently. In Excel, each cell is a unique entity unto itself. EVERY CELL can be something else. In Access, the cells in a tabular grid are constrained by record layout definitions and explicit or implied data types. You can build an Excel spreadsheet with a column that you are using as a scientific number. You can then copy/paste a number from that column into another column that is text. (Or vice versa.) And Excel WILL NOT CARE. In Access, try that and you might get a type misatch. Therefore, I would expect bizarre behavior in trying to do a bulk copy/paste in any grid-like display in Access.
Can this happen? Yes. Does it happen for you? Only if your users can get to grid-like displays.
This is getting long. I'll start a new one.
