Is it obligatory to immediately research the ruling on a mistake that occurred during prayer when in doubt about its invalidity, knowing its nullifiers, especially if the mistake relates to preventing some limbs from reaching the ground during prostration, standing, and sitting due to a thick or thin prayer rug?

Prayer is the second pillar of Islam, and a Muslim must learn its rules, including its pillars and nullifiers, after learning the rules of purification. If mistakes invalidate the prayer, it must be repeated within its time or made up after its time has passed. As for praying on rugs, whether thin or thick, it is valid by consensus.