After a jumper successfully cut away from a diving, spinning, line-twist malfunction and landed safely under the reserve, a rigger inspected the recovered main and was surprised to find that one soft link was installed with the lines twisted 180 degrees off from the riser and that the other had the lines installed in the wrong order and improperly secured. In all probability, none of these problems led to the cutaway, but any of the improperly secured links could have released at any time, possibly when the jumper was too low to recover from the resulting malfunction.
A jumper may install their own soft links but should do so under the supervision of a rigger. Most importantly, if a jumper has any questions about maintaining their gear, they should ask. Soft links are extremely reliable but, like all skydiving gear, they must be assembled correctly.