WhatsApp surpasses the likes of WeChat, Facebook Messenger and Skype in terms of monthly users, according to Statista.
The software is regularly updated by the firm, adding new features and functions for fans.
A number of new tools for the software are expected this year, including a dark mode and fingerprint authentication.
The former looks set to capitalise on the rise of dark themes that rose to prominence last year.
Meanwhile, the second will surely offer a new layer of security for users.
However, it appears the app is unexpectedly deleting some messages for Android owners, leaving many disappointed and frustrated.
WABetaInfo, an outlet renowned for trawling through early WhatsApp code and builds to garner a glimpse into forthcoming features, recently tweeted out the testimony of a user stating their chat history was disappearing.
The message read: “Since last month chat history has been disappearing chronologically.
“Now that trend has changed, every morning I find one of two chat history has disappeared.
“I’m using a Moto G4 Plus mobile and recently got to know through Google search that there are many people facing the same issue.”
In response to the initial tweet from WABetaInfo a number of WhatsApp users insisted they were dealing with similar problems.
One said: “I am facing the issue from June 2018. I am losing very important old messages.
“I sent too many emails to WhatsApp, now they stop responding to me.
“I tried everything including reseting my phone, a different WA version, changing phone, but no use. Still not solved.”
Another wrote: “Chats older than June 2018 are gone.”
A third declared: “I discovered this a few weeks ago when I went to look for the first message I sent to my wife in 2014.”
A fourth remarked: “Yes, some chats from 2015 of mine has disappeared randomly.”
The comments from Twitter users suggest the problem is mainly affecting older chats, but some newer threads may also be plagued.
Moreover, notes from users seem to indicate there is no cohesive pattern to how and why some messages are disappearing.
That means it is currently unclear if WhatsApp has directed the move or if such app behaviour is the result of a bug.
The firm has not commented on the matter or stated whether a fix is in the works if the app behaviour is unintentional.