Runway Alignment Issue / Flight Plan Alignment?

I had a full flight plan integrated from simbrief and on approach I realized my aircraft was going a little off track so I had to turn on the ILS to align with the runway, is this normal or does the flight plan align you with the runway and all you have to do is enable ILS?

This is not a bug.

The flight plan guides you to the airport. The ILS guides you to the runway. They’re not the same thing.

You should activate approach mode when it is time to intercept the approach.

ATC will say something like:
ATC: callsign, you are 47 mi southeast of OHare. Expect ILS 28R approach via VOGLR transition. Cleared to VOGLR.

This tells you to punch in the ILS28R approach. At some point, when you get closer to VOGLR intersection, you will look for the ILS diamonds (glass cockpit) or start to look for NAV instruments to come alive with landing system.

In real life, this is when you’d be cleared for the approach, but MSFS has some weird logic such that the approach clearance comes much later.

At this point you stop following flight plan and start following the instrument approach.

Cheers.

I don’t use atc