The disclosure relates generally to sequential state elements (SSEs), triple-mode redundant state machines (TMRSMs), and methods and systems for testing triple-mode redundant pipeline stages (TMRPSs) within the TMRSMs using triple-mode redundant SSEs (TMRSSEs). The SSEs, TMRSMs, TMRPSs, and TMRSSEs may be formed as integrated circuits on a semiconductor substrate. Of particular focus in this disclosure are SSEs used to sample and hold bit states. Embodiments of the SSEs have a self-correcting mechanism to protect against radiation-induced soft errors. The SSE may be provided in a pipeline circuit of a TMRSM to receive and store a bit state of a bit signal generated by combinational circuits within the pipeline circuit. More specifically, the SSEs may be provided in a TMRSSE configured to perform self-correction. Also disclosed are methods for using the TMRSSE to test redundant pipeline stages of the TMRSM.