Submitted by rvierdiiev
https://github.com/code-423n4/2023-01-popcorn/blob/main/src/vault/adapter/abstracts/AdapterBase.sol#L158 
https://github.com/code-423n4/2023-01-popcorn/blob/main/src/vault/adapter/abstracts/AdapterBase.sol#L456-L472
Strategy cant earn yields for user as underlyingBalance is not updated when strategy deposits.
When someone deposits/withdraws from adapter, then underlyingBalance variable is updated with deposited/withdrawn to the vault shares amount.
Only when user deposits or withdraws, then AdapterBase changes totalSupply(it mints or burns shares).
This is how shares of users are calculated inside BeefyAdapter:
https://github.com/code-423n4/2023-01-popcorn/blob/main/src/vault/adapter/beefy/BeefyAdapter.sol#L122-L133
As you can see, when user provides amount of shares that he wants to withdraw, then these shares are recalculated in order to receive shares amount inside vault. This depends on underlyingBalance and totalSupply.
Each adapter can have a strategy that can withdraw harvest and then redeposit it inside the vault. In this case users should earn new shares.
When adapter wants to deposit to vault it should call strategyDeposit function. 
https://github.com/code-423n4/2023-01-popcorn/blob/main/src/vault/adapter/abstracts/AdapterBase.sol#L456-L461
This function is just sending all amounts to the vault.
But actually it should also increase underlyingBalance with shares amount that it will receive by depositing.
Because this is not happening, underlyingBalance always equal to totalSupply and users do not earn any yields using strategy as convertToUnderlyingShares function will just return same value as provided shares.
So currently users cant earn any yields using strategy.
Note: this was discussed with protocol developer and he explained to me how it should work.
VS Code
Increase underlyingBalance with shares amount that it will receive by depositing. But do not mint shares.
RedVeil (Popcorn) acknowledged 
LSDan (judge) decreased severity to Medium and commented:
