Can wire transfers get lost, and what are the common reasons this happens?

A wire transfer is never lost per se. There are literally 100s of scenarios as to why a wire transfer is either not returned or not credited to the end beneficiary. Most of the time it is an administrative (system or human) error in the handling of the wire transfer. It is usually stuck somewhere, held in abeyance until someone comes looking for it and fixes (reverses?) the error or until such time it is noticed missing and is found.

There are also times at which communication is simply going to the wrong person. For example, if a wire transfer is happening from Los Angeles to Berlin, and the intermediary bank is in London, the UK bank could be asking the LA bank for some information pertaining to the wire, but the LA bank wire department might not be relaying it down to the correct branch to the end customer who is running from pillar to post, trying to ascertain why the wire has not reached its destination. This is a very common occurrence.

Other reasons may be that it is stuck for legal reasons and the reason cannot be disclosed to you by law. For example, if the wire transfer was part of a flag on a sanctioned person, they (the bank) might not let you know, and might contact the federal authorities who take their own sweet time to respond back and then determine the next plan of actions (a process that can easily take a couple of months even).

The reasons are plenty. Some might be trivial and the bank might hide its embarrassment (on an internal faux pas) or they make take time to fix it and let you know in a blurred manner that there was an issue and it has been resolved.

On the flip side, by law, they may not be able to tell you why the wire is being held up.