Al-Mandoh made a complaint to the boardroom against the 37-year-old, accusing the former Ahli keeper, who's serving a lengthy ban, of affronting him and his club during training.
The trainer believes Al-Hadari is psychologically affected by the infamous four-month suspension, which became effective in October.
"He insulted Zamalek and everyone around him," Al-Mandoh told FilGoal.com. "This is way beyond acceptable. He just verbally attacked everybody.
"He was angry because of his overdue payments but what really makes him frustrated is his ban.
"It happened during his special training session. I complained about the incident and Zamalek chairman Galal Ibrahim assured that he will hand him severe punishments."
Al-Hadari, who turns 38 in January, was sanctioned by FIFA for violating his contract with Ahli in 2008 to join Swiss side Sion.
He lodged an appeal against the ban, which was imposed last year, but it was turned down by the Swiss Federal Court last month.
Harshly sanctioned
Zamalek interim president Ibrahim and football director Ibrahim Hassan voiced dissatisfaction over Al-Hadari's unjustifiable actions, saying he won't beat the rap.
"I don't know why Al-Hadari flew off the handle but in all cases he will be harshly sanctioned," Hassan stated.
"If he wants to leave he can do so politely. We stood by him when he faced problems and he owes us that much.
"He was eager to join Zamalek and it's hard to tell what makes his attitude drastically change.
"Maybe the interest from Harras Hodoud in his services prompted his new behavior."
Al-Hadari joined Zamalek in the close season from Ismaili but was hardly settled at the 11-time Egyptian champions.
Alexandrian side Hodoud are understood to be interested in his services.
Too Much to Handle
On the other hand, Al-Hadari categorically denied verbally assaulting Al-Mandoh as widely claimed but said he 'won't set foot' in the Cairo side again.
"There hasn't been any tension between Al-Hadari and Al-Mandoh during training," a statement on his personal website reads.
The highly-rated custodian later told Modern TV: "I won't set foot in Zamalek again. This is too much for me to handle.
"I would rather move to a foreign club but if I stay in Egypt I will join an outfit where I can receive better treatment, like Harras Hodoud."