You can check for limb twist by drawing the bow and letting it back down slowly. If a limb is badly twisted, the string won't reseat in the string groove on the recurve. Rather, it will run to one side. Just viewing the bow along the string, from tip to tip, will detect a smaller twist if one exists.
I've shot bows with twisted limbs, and didn't notice poor arrow flight associated with them. I'd look to other things. Has your brace height changed, nock point slipped? Are you using different spine, length, shafts? Different weight heads, etc. Good luck.