Yes they do if they are mature and are not a variety of green tomato.
Even the "green" varieties will turn yellow.

They should be firm but not hard. What was the texture and taste of
the ones that turned?


OK, then maybe what I had really were green tomatoes. I was just
surprised to see the orange-red color. It was getting a bit soft
as it turned this color. Taste was quite fine, mildly sweet. When
these were green they tasted quite good. I got worried about the
color change because of rumors that green (unripe red) tomatoes
are at least mildly poisonous and perhaps carcinogenic. I have
not been anxious to compare the taste of unripe (still green) red
tomatoes. I have yet to look seriously into these helth allogations,
but have Medline access....

Dominic