Brown out recovery and sleep time acracy

Coming from esp32 Lora. Loving the way the Heltec wakes from sleep with variables in tact and so i assume the program continues from where it went to sleep. My question is how does the Cubecell deal with brownouts is it a full soft reset or as per sleep . It’s hard to watch the cubecell while it’s not connected to a USB port and running above a brownout voltage. I ask because after time the Cubecell seems to stop waking and transmitting it’s battery voltage. Do i need adaptive duty cycle to keep the battery voltage above a brownout level? Also i have started coding for a soil humidity sensing Cubecell and another Cubcell to relay the data to my location using listening only esp32 lora connected Wifi to Thingspeak.
Prior to purchasing the Cubcell , i have done a few tests on two esp32 lora boards and managed to sync a wake up sleep time of 20 minute sleep with 10 second receive window. Has anyone done similar test for the Heltec Cubecell board? With primitive time stamps on arduino serial for a cubecell sleep wake of 10 minutes the time stamp shows about 7 seconds deviation.

The cubecell will continue to run from where it stopped after the sleep refresh.