Marcus, Alexey, thank you for your ideas. I just did several builds to see how to make things work. Here's what I got: make clean && make - does not work (the problem persists) make distclean && ./configure && make - same as above git clean -xdf && ./configure && make - this one finally worked. I'm not sure what's the difference between the above, but I'm going to stick to git clean for the time being.
Thanks again Daniel