Counting M1R and M1L in pattern

I have a pattern that starts with 21 stitches between the markers. The instruction is to YO, K9, M1R place marker, K1 *M1L, K9 YO. Every time I do this I am coming up with extra stitches on the second half * there are 11 stitches. Is that because you do not count the stitch following where you do the M1? I am confused please help.

It might be that there’s a typo and the markers should be before the first m1 and after the 2nd one. Can you link to the pattern and we can take a look at it? Because there’s no instruction for where to put the 2nd marker and there’s only one * where usually there’d be 2 of those too.