The Ask site is not, I repeat, not the customer service department of LibreOffice. It’s a place where users ask for help and other users help them, when they can. Those users helping other users aren’t paid for that, and more often than not, the OP doesn’t even bother to come back and say “thank you for your time and effort”. I know @Keme as a very helpful and very polite person, his comment is spot on. If you want help, you need to state what your problem is, and in some cases you have to be very specific indeed. If you don’t like that, go somewhere else.
We don’t “blame the user” for developer errors. We may suggest the possibility that the user made a mistake. The purpose is to cover all bases, not to place the blame. Most users will accept that as a possibility, but some will take offense where none is intended. This time the OP investigated based on the comments given, and did not arrive at a solution. The answer from SergioB was later accepted as a solution, so it must be the one.
@Darkeen: I submit that your suggested solution, to save in Microsoft format and disable warnings, is the wrong one unless you are using Microsoft software. If someone follows your advice (perhaps not so likely) and it causes data loss (also not likely but very much a possibility), you are the one to blame.
There you have it, sometimes we DO place the blame. Satisfied?
Small update to the published solution: instead of winrar save as a flat xml odf file in Libre Office and then use Notepad++ (or other text editor) to find and replace: value-type=“float”* for office:value-type=“string”. I did a replace all with no problems but this may depend on your file.