Dante_RB,   Being that you are using SFP+ base t Transceivers that would convert to cat6a, there should not be any loss of performance or operational issues.   Now if you were wanting to use one interface running fiber and one running cat6a that would not work.   Let me know if this helps.      
Hello, can VLTi be configured on 2xS4128F-ON switches via the 10Gb Fiber ports (using 4*10Gb SFP+ baseT optics & CAT6a cables ) . i'm aware there are 2x QSFP28 ports, but i need to confirm whether the above request could be achieved without any performance or operation issues. Thanks in advance!
VLTi config with 10Gb BaseT optics