WhatsApp showing me online though I am not

My phone (iPhone 11 - version 16.1) was completely switched off and the before it was turned off, WhatsApp was open.

I've plugged it in and left it for charging. Meanwhile, my wife is claiming that she saw me online and offline 2 times (There are no other instances or active sessions of my WhatsApp on any other devices) on her mobile (she is using Vevo - Android). My wife is indeed accusing me for not responding to her on WhatsApp (while I am not online at all).

Is there any possibility of WhatsApp showing me online/offline intermittently when the iPhone is turned on (in the case of the iPhone getting switched off due to no charge and last used was WhatsApp).

Please do let me know if there is any known issue as I am being accused by my wife which turned out to a heated conversation and she left the house. Thank you in advance!