Air Carrier First Officer reported a fumes event in the cabin while on an unrelated mechanical flight diversion. The flight continued to the diversion airport and landed safely. No information provided regarding the cause of the fumes.

Narrative

Enroute to ZZZ from ZZZ1 we had an MEL for the APU inoperative and in cruise we received a GEN 1 OFF caution message. The crew ran the QRH as instructed and the GEN 1 OFF message extinguished and did not come back. Shortly after the we received a 'FMS not available message' in the FMS box. The crew proceeded to ZZZ via ATC vectors and conducted a visual approach backed up by the ILS in ZZZ. After landing Company Maintenance Control was contacted and the 'GEN 1 OFF' message was written up as an info only due to the belief that it was a transitory anomaly. Before T/O for the flight to ZZZ1 from ZZZ we received a GEN 1 OFF caution while holding short of the runway while burning fuel to get below MTOW. The crew contacted Dispatch and Maintenance Control and the decision was made to return to the gate and outstation maintenance was contacted. Maintenance performed operation checks of the APU and reinstated it to service and the constant speed drive was MEL for the GEN 1 OFF caution message. The crew followed the MEL operational procedures as well as confirmed that the maintenance procedures were completed. Shortly after level off in cruise going to ZZZ1 from ZZZ the crew received an 'APU OIL PRESS' caution message. The Captain transferred the controls to the First Officer and ran the QRH. The crew determined that the APU was an operational necessity during the QRH procedure because turning off the APU would leave us in single generator operations. Shortly after that the crew received an 'APU OIL TEMP' caution message. The Captain ran the QRH again and decided it was now time to shut down the APU and land at the nearest suitable airport due to the single generator condition. After speaking with Dispatch through ACARS and ARINC (Commercial Radio) the decision was made to divert to ZZZ2. During the diversion the crew received clearance for an overweight landing (1;000lbs over; 48;000lbs). while being vectored for the approach for XXC into ZZZ2 the flight attendant called the cockpit and reported that the cabin had a 'hot stinky smell 'in the cabin. The cockpit crew treated this like a smoke/fume event and requested ARFF (Airport Rescue and Firefighting) trucks be present on landing and the Captain [received priority] (The FO agreed with this decision). On landing the aircraft was met with ARFF trucks and ARFF fire command inspected the brakes and the aft equipment bay. The ARFF commander reported 'Oil everywhere' in the aft equipment bay. The aircraft was taxied safely to the gate and shutdown afterwards. Company Maintenance was contacted.The event occurred due to a compounding of factors. Mainly the continued on and off deferral of the APU from Date-Date1. After the incident on Date1 the write up made the 4th time the APU had been written up and previously crews experienced similar issues with it as written in the Logbook Entry. The continued deferral compounded by the issues that day with the GEN 1 OFF caution message led to a scenario where it was no longer safe to continue as planned to the destination and the a diversion was the deemed the safest course of action. Fixing of root causes of maintenance related issues instead of deferrals and operational checks. Especially items that have a reported pattern of repeating and have been reported by multiple flight crews.