I have been slowly watching spots appear on the new leaves of my philodendron.

They are small, brown and dry (similar in look to leaf tips when under/over watered). They don't appear on the leaves that the plant had when I originally bought it. I keep the plant in a window (maybe too bright? I have since pulled it away from my the window sill) and water it when the top layer of soil is dry to the touch (about a 1/2" down). It is planted in a mixture of soil and mulch, with very good drainage.

I've done a bit of internet searching, (and am now petrified that it's a bacterial issue) but I'm at a loss as to what could be causing this! Has anyone had a similar problem? (am I just a helicopter plant-mom?)

Thank you!