When the dates on TAF are more than 04 hrs from the 1st day of the month the translation from UTM to Local time is okay because here in Toronto, the local time = UTM - 4 in this time of year. However, when the TAF time is between 00 and 04 hr of the first day (similar to the one that is bold in the following TAF) the translator can't recognize that UTM-4 will be still in the current month (in UTM FM010000 is on 1st day of OCT but its local time is 30 OCT. However, the translator thinks the 010000 is 1st day of SEP therefore its local is AUG 31 (which was a Monday). For that reason, the following TAF will be translated as:
301338Z ====> 30 SEP Wednesday (local)
FM301500 ===> 30 SEP Wednesday (local)
FM301800 ====> 30 SEP Wednesday (local)
FM010000 ====> 31 AUG Monday 20:00 (local) which should be 30 SEP Wednesday 20:00 (local)
FM010400 =====> 01 SEP Tuesday 00:00 (local) which should be 01 OCT Thursday 00:00 (local)
TAF CYTZ 301338Z 3014/0114 25015KT P6SM FEW050 SCT150 FM301500 24018G28KT P6SM SCT025 BKN050 FM301800 24020G30KT P6SM BKN030 TEMPO 3018/3024 6SM -SHRA BR BKN020 FM010000 24015KT P6SM -SHRA BKN020 FM010400 25012KT P6SM BKN015 RMK FCST BASED ON AUTO OBS. NXT FCST BY 302000Z