Interestingly, according to the paper you suggested it appears to include a similar test in pseudo code https://htor.inf.ethz.ch/publi cations/img/hpclocks.pdf (see Listing 3 in paper). Unfortunately, removing the test in the release protocol did not solve the problem. The race condition is much more difficult to provoke, but I managed when setting the size of the communicator to 3 (only tested even sizes so far).