3.1.5 losing or gaining hight in yaw in loiter

hi quad developed strange behaviour when in stabalize and I put yaw in with out moving throttle hight remains constent but in loiter yawn one way quad climbs and the other yawn quad losses hight
throttle not moved barometer has foam supplied over barometer sun was out but havnt had this problem before could some kind sole look at my logs maybe make a suggestion
cheers stuart

:smiley: all sorted it was the sun very bright and low in the evening changed pink foam for black in apm and its cured the problem sun seamed to be bleading in through the side and upsetting barometer