Occasionally, an EX4300 might hang or get stuck immediately after a "commit check" operation. When you enter the commit command, the configuration is first checked for syntax errors (commit check). Therefore, any configuration change runs the risk of running into this issue.
During a commit check operation, temperature thresholds are programmed. A rare occurrence of an inaccurate low threshold write due to bit errors may result in over temperature threshold being hit causing a shutdown. This issue is being addressed in the 20.4R3-S9 and 21.4R3-S5 releases. The fix removes the unnecessary register writes during the commit check and confirms values written to the register via a read-back.