The incident occurred late on Friday night, with flames and heavy smoke engulfing the club’s dressing room area.
Barcelona have described the situation as a “major error,” that significantly impacted the match.
Attacking talent Wilfried Zaha is suspended for Charlotte FC due to yellow card accumulation.
The manager had criticised decisions involving a VAR official, suggesting bias and questioning the integrity of officiating.
Lecce’s supporters drew a €10,000 penalty for throwing a firecracker and multiple smoke bombs onto the pitch.