Could lumpy patches on rendered external walls indicate damp issues?

[Nonstandardsolution]

We’ve been to see a house today and on a few of the external walls there are lumpy areas - is the damp? House is rendered over brick and about 70 years old - ex council house.

Is that internal or external?

Yes, that would be my first guess from your picture.

This is an internal wall between the bathroom and hallway. (Back door is pictured)

This is a zoomed out pic

Either damp or a previous water ingression (a leak from somewhere)