is a common thing
I've found at about 6-8 month cycle where things get worse then they sort themselves out and fall into place.
I think what is happening is over the course of a few months we gradually acquire new abilities and integrate more different elements into our movements and at some point we get over loaded with just too many elements and that results in a getting worse as we try to balance all these elements in an new or higher level.
There are so many things going on and sometimes we get a bunch of them just so at just the right time and things really seem to 'click' while at other times the timing or coordination is just slightly off and things fall apart.
10 years into it and it still happens on this 6-8 month cycle for me. I see it similarly happen to others. Even sensei goes through cycles it is just harder to see the 'slip' and sensei is able to recover much more quickly (like milliseconds).
See my blog about the moon cycles as a way to systematize dealing with the ebb and flow of things. Just one more straw to load up on the camels back.