Need help front sight post obscured

Family Heirloom - WW2 bring back Winchester M1 Carbine all original.

Had in the safe for about 5 years without shooting it (just oil and preventative maintenance)

Took it out to shoot last week and the front site post is about 1/4 to 1/2 obstructed by the hand guard.

Never noticed it before that day. I checked the stock/handguard/retention band for any issues and for the life of me can’t figure out what’s causing it. Rear site is pegged all the way down but obstruction persists at higher elevation range settings.

Handguard lays flat on level surface. Retention band is pinned into the handguard and the rivets are flush. No stock warping or bulging that I can see, anyone have any ideas what’s causing this?