Usually the water filling up the flush valve in the tank. If it's bugging you, you can change the flush valve to a new one.
When a toilet is flushed, the rushing water creates vibrations in the pipes, which can produce a high-pitched noise due to the rapid movement of water and air in the plumbing system.
When a toilet bubbles when flushed, it is usually due to a blockage in the plumbing system. The blockage causes air to get trapped in the pipes, leading to the bubbling effect when the toilet is flushed.
When a toilet burps when flushed, it is usually due to air trapped in the plumbing system being released. This can happen if there is a blockage or restriction in the pipes, causing air to get trapped and then released when the toilet is flushed.
I do not know if popcorn can be flushed down the toilet. So, I wouldn't try it.- Ashton Smith
The discharge line (soil ) may be slightly back pitched so it takes longer to drain
Toilet bubbles appear when flushed because of air trapped in the pipes or a partial blockage in the drain. This can happen even if the toilet is not fully clogged.
The sewer
Your toilet may be leaking from the bottom when flushed due to a damaged wax ring seal or a cracked toilet base. This can cause water to seep out when the toilet is flushed. It is important to address this issue promptly to prevent further damage and water wastage.
Depends on if it needed to be flushed or not.
Bad venting
Water and waste
The toilet leaks at the base when flushed because the wax ring that seals the connection between the toilet and the floor may be damaged or worn out, allowing water to escape.