RIO Powerflex Trout Leader

I use the 12' leaders when fish get spooky, and Front Range is only place I can find them

I purchased two packets of three 5 and 6x leader as well as a spool each of 5 and 6x tippet. Knots held, but both leaders and tippets failed mid-line while hooked up to 15-18” trout. Very frustrating. Switching back to SA leaders and tippet material.