When driving the main race of the Canadian GP in Driver Career Mode (Long Race), a red flag came out on lap 17 of 35 - this was the same lap that I was pitting for new tyres. The countdown for the red flag coincided with me entering the pit lane, and pressing the "A Button" to enter the pit box. This then led to a return to the garage & strategy change, although I didn't adjust my strategy.
When the race resumed, I was on a new set of tyres - this was confirmed by checking the Race Director as well as the Tyre Wear MFD Screen. However, even though I had pitted for new tyres, the Pit Information Screen on the MFD still showed Lap 17 as the Pit Window. Furthermore the "Tyre Status" Radio Message resulted in the "high wear... box lap..." response. However, on lap 24 the automated radio message "no tyre concerns" was played.
The only other driver to show more than 1 set of tyres in the Race Director, was the car that crashed & brought out the red flag - all other drivers were still on there original tyre. However, they remained at the same distance behind me, even though I was on a fresh set, and they were on there original set (according to the Race Director)
On Lap 33 of 35 two of the AI drivers pitted for new tyres - In the Race Director, those drivers now had to sets of tyres against there names.
Finally, at the end of the race, the drivers that finished with only one set of tyres against there name, including the drivers that finished 2nd and 3rd remained in those positions, and weren't affected by any penalties.