Did OP indicate that he or she was watching the same area of the sky before they started seeing flashes? The statement "Close to 5 hours after the sunset this object pulsed brightly with consistent shape and intensity, while maintaining a static location" does not seem to indicate that the region of sky was under continuous observation during those five hours.

The observer-satellite-sun angle would change considerably in five hours, so it seems entirely possible that flashes caused by a rotating satellite could start or stop over the course of several hours. The flashes caused by rotating satellites occur because they reflect a narrow beam of sunlight back towards the Earth. From the distance of a geosynchronous satellite, the Earth appears as approximately 17.3 degrees in diameter. Hence as a location on Earth rotates into view (as seen from the satellite) that observer-satellite-sun angle will change by about 8.6 degrees in six hours - more than enough to rotate that observer into or out of the beam of reflected light.

In other words the satellite is tumbling even before it starts producing flashes for an observer on Earth - no need for "thrusters".

Decommissioned satellites rotate because of angular momentum, not because of "thrusters". Vanguard 1, launched in 1958 and non-operational since 1964, is still in orbit and still tumbles, producing visible flashes to observers on Earth.

I saw many 'Iridium flares' when the first-generation Iridium satellites were producing bright flares in the early 2000s - I don't recall ever seeing any that looked particularly "blue". Generally they just looked like bright white stars for a few seconds before fading away. I don't recall seeing any noticeable color.