This bug is regarding the map limit for creating maps as the current limit (32768). After this number of maps is reached every new map will overwrite the first maps created in that world and will be completely empty and have ID 0 this is due to the size limit of a 16-bit signed integer. Thus I am proposing to use a 64-bit signed integer with a limit of 9,223,372,036,854,775,807 maps, This new limit will likely never be surpassed and will ensure that maps will never be overwritten.
The main reason for this report is that there are servers that have been online for almost 10 years now and have map art that doesn't work anymore due to this. (I mainly refer to 2b2t and Minecraft.online).
Requesting the limit to be increased is a feature request. Older maps being overwritten when the limit is reached would be a valid bug though, and we don't seem to have a ticket for that. If you want to create a ticket about that, feel free to do so.