If it tastes wrong then it probably is Galt... they should give you ane exchange easy enough am sure.
Flax goes off pretty quickly... I remember a study on milled flax seed which showed that even when properly packaged in air tight cellophane within just a few hours of milling the seed, 28 days later a significant proportion of the fatty acids had gone rancid.
The biggest excellerant of rancidity for fatty acids in stored bottled oils is light rather than heat...when not talking about cooking, constant exposure to strong light is a major catalyst of the reaction that makes the oil rancid, being able to transfer more total energy over time than a merely 'warm' environment... while rancidity occurs faster when exposed to air also, the light still has an effect without air. I always marvel at the 'healthy oils' supermarkets sell, all in nice clear bottles exposed to bright light for eighteen hours a day... :no: