Help with Ficus Tree

[hp5bonsai]

For a couple days I’ve been noticing these leafs with black spots emerging, overall the tree looks in good health but these brown leafs keep appearing it hasn’t been in direct sun for it to get sunburnt so I’m wondering what could be causing this, any suggestions?

 

[Shibui]

There's a few things can cause ficus leaves to change colour so we'll probably need some more info.
For a start, where in the world. North is end of winter but South it's just Spring now. Seasons are all important with bonsai and local climate pays a big part too so it pays to add a location to your personal profile so we don't have to keep asking.
Humidity and soil moisture seems to play a big part in Ficus leaf health. Where do you keep the tree? How much direct or indirect sun does it get each day? How often is it watered? What type of soil is it planted in and how long since the last root prune or repot?
A shot of the pot and trunk with something for scale might help too.
Do you fertilise? with what? How often?

Let's see if any of those answers give any clues before we bombard with more.

 

[penumbra]

Based upon the picture and comparing with my own ficus plants, I appears that it may be abandoning its oldest leaves which is normal. It has fresh new growth I see.
Everything posted above by Shibui needs to be considered and addressed.