Drinking a fire resistance potion and standing in fire, on magma blocks or lava works normally, but if you quit and rejoin and then try to stand in fire, on magma blocks or swim in lava you still get hurt with the effect on.

Steps to Reproduce

• Make a 3x3 puddle of lava or magma blocks or place fire on the ground.
• Give yourself fire resistance potion.
• Stand in the puddle of lava, on the magma blocks or fire you placed on the ground.
• Reopen your world.
• Observe that you still have fire resistance status.
• Notice you're not standing in lava anymore (This happened only if you were standing in lava before you reopened your game)
• Stand in the lava or on magma blocks or walk over the fire you placed again and notice that you start taking damage until you eventually die. Why is this?