I have hade problems with false triggering of the MCP9510HT-E/CHMCP9510HT-E/CH when pcb was exposed for high levels of HF EM-fildes. Problemes solved by adding a small footprint 22nF ceramic cap very close to VDD and GND. Also keep the R close to the chip and connect the GND side of Rset to the gnd pin of the chip and not to the groundplane. With this improvement the chip maintain stabile even if exposed to all kinds of CS test, ESD test and RS tests with very high levels of HF EM-fields. Basic EMC work, but good to keep in mind due to fan controll often are very important for system realibilty.