What happens in incognito mode should stay in incognito mode, but this is not always the case. A few years ago, it was possible to review the videos that had been seen in incognito mode, something that fortunately is no longer possible. However, it is still possible to know how many times and how much have you opened incognito mode, both in Google Chrome and Firefox.
The good news is that this detailed log will not be active on all android phones and that, on those where it is, you can prevent it from happening with a few minor tweaks in the notification settings.
How to see when incognito mode was opened
First let’s see why this data is visible and where it is exactly. It is a problem similar to the one that allowed the recovery of videos that had been played in incognito mode a few years ago, which has already been patched with successive updates.
In the past, when you played a multimedia element on any web page, whether in incognito mode or not, the name of the video was displayed in a notification. Later, it was possible retrieve that notification from android notification history, present in some Android mobiles and that must be activated manually from Android 11.

Incognito videos no longer show your name in notifications (right image)
This problem is now fixed, but another is still active: every time incognito mode is opened, both Google Chrome and Firefox show a notification with the text “Close all tabs incognito”.
Checking the notification history you can see later what time and on what day this notification was displayed. What’s more, if you open the incognito mode several times during the day, they will be registered every time.

Of course, there are a number of prerequisites. The mobile needs have access to the notification history and make it active. Android mobiles that do not include a serial notification log can still save the notification history with third-party applications, such as Notification History Log.
In this record you can see when the notification of the incognito tab was activated in Google Chrome and, in the case of Firefox, it also indicates that it was used to play multimedia content. As it does not put the name of the clip, it can be deduced that it was done from the incognito mode of the browser.

From Chrome you can tell that incognito mode was opened. From Firefox, also that multimedia content was played, but not which one
How to hide your sessions incognito
In the event that you prefer not to be registered anywhere when you have opened incognito mode on your mobile, the easiest way to do so is disable notification history from the mobile settings, if possible. If you have an application that saves notifications, disable it or add the browser as an exception. If the mobile does not have any way to register the notifications, then you do not need to do anything.

In case it is not possible to disable the notification log, there is still something you can do: disable Google Chrome notification. Going to the information of the Google Chrome application, in the Notifications section, you will see that there is a notification channel called Incognito. Disable its notification, and there will be nothing to record in the registry.
In the case of Firefox, the name of the notification channel is slightly different: Private browsing session. You may also be interested in deactivating the notification of Multimedia, although in this case you will lose control of the playback also in your normal sessions.

The notification channels of Google Chrome (left) and Firefox (right)
Of course, remember that these notifications are there for remind you to close tabs in incognito mode, otherwise they will appear when you open the browser, which can be even worse than the record in the notification history.