Is it normal to urinate in strange places?

I think it's not uncommon. And it can be difficult to know what is triggering this loss of orientation to place.

(When you add up all the different cognitive steps involved, there are quite a lot and they have to be maintained throughout the whole process. Feeling urgency. Recalling appropriate response. Remembering bathroom location. Locating bathroom. Adjusting dress. Peeing. Paperwork as necessary. Readjusting dress.)

It might be worth reporting the change in behaviour and seeing if anything can be done - signage, lighting - to help him pick his time and place!