dual XGS1010-12 10gig passthrough

So i have dual of these XGS1010-12 switches both with two 10gig sfp+ ports. On one switch I'm using both SFP+ 10g ports. One to connect to my router and the second port to pass through to my second XGS1010-12 switches 10g sfp port. I seem to have a lot of issues were this is disconnecting the second XGS1010-12 when i put close to 10gig bandwidth use over it. I'm unsure if this is not supported on this switch. It said it could be use as core backbone which is what i was trying to use them for having one pass the 10gig onto the second switch. Could this be a issue with the SFP+ i have they are all QSFPTEK 10GBASE-T SFP+ RJ45 Transceiver, SFP to rj45 Copper Module. I have used a tester to verify sfp and cable to be able to pass and receive 10g without issue. This leads me to wonder if the switches have a issue.