I rewatched a bunch of the episodes there and I now remember one of the things that really bugged me about the series: the walk and run cycles.
They're not synced properly to how fast the characters are moving. Whenever characters are running anywhere in particular, they move faster than they're running, so it makes them slide across the ground really strangely. This is really evident with the Grimm animals who look like they have less time put into them than the humans, but it can still be seen in pretty much any fight scene involving running between the fights.