On the 965, there is an issue with the amount of data the Stryd and Core write to the fit file and it causes the Stryd data field to crash unless you change the default settings for the Core data field to not write the charts to the file (i.e., code 32).
Core has said this is a limitation of the 965 and I'm wondering if the issue is resolved on the 970. Has anyone been able to use the Stryd and Core data fields simultaneously?