map.getBounds() return values outside visible map

[didulis]

• I've looked at the documentation to make sure the behavior is documented and expected
• I'm sure this is a Leaflet code issue, not an issue with my own code nor with the framework I'm using (Cordova, Ionic, Angular, React…)
• I've searched through the issues to make sure it's not yet reported

Application, developed by us, requests from API coordinates of points for map bounds retrieved by map.getBounds() and adds markers on the map, but sometimes these markers are added outside visible area.
For testing purpose, to see if this behaviour is only in our app or in general, I created this fiddle - https://jsfiddle.net/kzLohbac/1/
(I convert decimal degrees to "deg min sec" format only to simplify visual comparison of coordinates)

Steps to reproduce
Steps to reproduce the behavior:

• create map widget
• output map.getBounds() coordinates
• attach "mousemove" to output coordinates of current mouse location in map
• slowly move cursor to any edge of visible map and compare last mouse coordinates with previously printed map.getBounds() coordinates (left edge with SouthWest longitude, right edge with NorthEast longitude, top edge with NorthEast latitude and bottom edge with SouthWest latitude)

Expected behavior
Returns the geographical bounds visible in the current map view ( https://leafletjs.com/reference-1.5.0.html#map-getbounds )

Current behavior
Some bounds visible in current map view differ from ones reported by map.getBounds(). And sometimes this difference is about half of the geographic second.

Environment

• Leaflet version: 1.5.1

• Browser (with version): Firefox 70.0 (64-bit), Google Chrome 78.0.3904.97 (64-bit)

• OS/Platform (with version): Fedora 30

• this example is as simple as possible

• this example does not rely on any third party code

[lukacg]

Try something like this:
bounds = new L.LatLngBounds(new L.LatLng(48, 15),new L.LatLng(49, 17)); map.fitBounds(bounds);

[didulis]

Just now I had time to test your suggestion @lukacg and map.getBounds() still returns values outside visible map