The following 3 devices constitute the majority of the users  who are facing the issues : 
Moto C plus, Lenovo A6600 plus and Lenovo K6 Power.

So can you please ask 1-2 users each using these 3 devices to follow the following steps :
  1. Restart the device.
  2. Download the following app : https://play.google.com/store/apps/details?id=com.easyx.coolermaster
  3. Once they have started using the Leadsquared app and Check-in is done, they should close the app and kill it from background, they should ensure the notification is showing  even after killing the app. 
  4. If the battery heats up, They should launch the cooler master app and check the battery temperature. Battery starts heating up after 37-38 degrees but smartphones can handle temperatures upto 45 degrees without any worry . If the temperature is rising more than that , they should immediately kill all the apps from the background if any apps are running and check if temperature has dropped after few minutes. If none of the apps were running then there is an issue with the battery. Generally, overheating also leads to the slowing of apps as Android reduces the CPU speed. 
  5. We  need the particular information when the battery is heating up like what activity were they performing(this should be appropriate) and also how long is the battery remains heated. This is extremely important for me to know. 
  6. They can follow the above steps when Leadsquared is open or in background after they have tried by killing it.  
  7. The following reasons contribute to battery heat up :- 
    Long duration call, playing graphic intensive games, frequently charging the phone or overcharging or they are working in hot temperatures and phone is exposed to sunlight for long hours specially in regions having high temperatures. Plus, devices with lower end CPU may heat up faster as they maybe running at full clock speed sometimes which leads to more battery consumption as well.