It is fairly common and not at all a new phenomenon for books to have
different titles when they are published by different publishers in different countries but the example you have of changing the title and the author and the main character names is the first time I have seen that. You would think that the author would want it to be found easily and that amount of change is confusing. Of course if the original book got rotten reviews maybe they are intentionally obscuring the source.
There are a few other times I have seen a book change titles or authors too, normally associated with going from traditionally published to indie published.
The first few (possibly all) of the John Rain books by Barry Eisler all have new titles now but he does provide the original title clearly. Apparently when they were first published the publishing house wanted the titles to be themed, "Rain Fall", "Hard Rain", "Killing Rain", etc. and when got his rights back he went back to the original titles he had wanted for the books rather than the themed ones that didn't have much to do with the actual story content.
Another example would be JA Konrath changing the name on some of his pseudonym's books back to JA Konrath instead of the pseudonym. Although in most (all?) cases I think he left the original pseudonym and make them "... and JA Konrath" so that they could be found by searching for either name. Again, this was a change made when going from traditional publishing to indie publishing and also to make sure his books were all easily discoverable.