No, when a watchdog triggered warm reset occurs the content in HPS L2 cache is not flushed by the Intel Stratix 10 SoC.
Any content in the HPS L2 cache is lost after the reset. This may prevent Linux having a complete error log for analysis after warm reset if the memory location used for log storage is cached.
Any critical error log content should be stored in memory non-cached memory. You may need to modify the memory attributes used by the log mechanisum driver to select on-cached memory.