That is definitely weird. Does the art on the text master page bleed off the page in either direction (even just part of the image box)?
I had that problem once and could never figure it out, so I ended up creating additional master pages in an unorthodox way.
For example:
On my new master page, on the left hand side I set it up as the chapter opener, and the right hand side was regular text.
On a second new master page, on the left hand side I set it up as the regular text, and the right hand side as the chapter opener.
Then I applied as a spread to the affected pages when I came across them. For some reason it worked.
To me, it sounds like InDesign is getting lost when it comes to that RH side when facing the chapter opener. (which was also the case in the job I mentioned).