Brown spot onPlant

I have had this plant about a month in my heavy planted 29 gal but never had one with these brown spots on one. what is the cause?

They are terrestrial leaves that are starting to die off. Leave them on the plant until the entire leaf is brown and then remove them. When the plant has terrestrial leaves and is submerged, it draws the nutrients out of the old leaves and makes new aquatic leaves. The terrestrial leaves are generally firm and can stand up when taken out of water, whereas the aquatic leaves can't support their weight when out of water and flop over.

Thank you for the fast reply. I haven’t heard that before , so I ll just wait it out then….