Why is this happening to me

For years I compose all me post in “notes” on my iPad and than copy and paste. For the last few weeks this, as seen below had been happening. What going on. No changes or updates on my device. In notes, the font size is the same as I am typing here but it font size increases and becomes bold after I paste 



[font=.SF UI Display][font=.SFUIDisplay-Semibold]Test, this is only a test[/font][/font]

You are "copying and pasting" the html.

Here is a screen shot of it happening to me

Just the typed subject. Only happening on this site and just started in the last couple weeks