Raid Time Keep Going - LAG?

I solo Gengar today with about 35 seconds left but Gengar dont fainted!!!! I keep attacking for 32 seconds even when Gengar has no hp and luckily at 3 second left. it fainted. Is this normal?
i used below pokemons
Gengar lvl 39 SB/SC
Alkazama - lvl 39 PS/F
Gengar lvl 30 SB/SC
Ttar - lvl 39 B/C
Ttar - lvl 39 B/C