This is an old problem with a couple of different causes. You can do some searching and you will find quite a bit written about this problem. Unfortunately, there is no one simply fix.
SACD_Extract has been used for a long time to extract dsd files from an iso file. At one point there was a bug in it that often caused this problem. There are newer forks of the software that help eliminate the click.
Some software/DAC combinations mute between tracks in such a way as to silence the click if it is there. That really depends on the specific software and DAC. It is something Wiim might want to look into.
You might want to download some of the free dsf files that are available and see if you still have the problem. If so, it seems like it might be a Wiim issue, although it is hard to know.
You might also try a different DAC if you can, although that is usually more of an issue with directly playing DSD files than when they are converted to PCM.