Why is HM Sultan Johor angry?

Malaysiakini - Chinese letter by Harapan councillor earns wrath of Johor sultan (extracts):

Johor ruler Sultan Ibrahim Sultan Iskandar has asked a Pakatan Harapan local councillor to resign if he does not know how to do his job.

This was after the councillor for Zon 8 Taman Bukit Indah, Chan Wei Kjhan, issued a letter in Chinese using the Iskandar Puteri City Council (MBIP) letterhead. [...]

Sultan Ibrahim said any official letters involving state government or local authorities must use the national language.

The letter was an invitation for residents to attend a dialogue with Perling assemblyperson Cheo Yee How and MBIP representatives to discuss a road divider. The letter was signed by Chan.

Prior to the sultan issuing the statement, Cheo apologised for any offence caused.

"The letter was actually written in the national language, with the Chinese and English versions only included as attachments," he said. [...]

Apart from the Bahasa Malaysia version of the letter, Chan had also written versions in both Chinese and English. Both carried the MBIP letterhead.

The issue of the letter was first raised by former Johor menteri besar Mohamed Khaled Nordin.

Cheo had accused Khaled of misleading the public by only highlighting the Chinese and English attachments.

Well, HM Sultan Johor is pissed off (anyone knows palace language for this term? wakakaka) because official letters in the state have never been multilingual.

I have two questions and one observation - I'll start off with the observation, to wit:

... that former Johor MB Mohamed Khaled Nordin was the sh*t-stirrer, wakakaka. His raising of the letter being in the Chinese language sparked off HM's ire, but as an UMNO man that's right up his alley, to ganggu Pakatan in the way Guan Eng had earlier ganggu Mahathir with the FM's Chinese language media statement.

By logic, it's a trivial matter as the Chinese and English versions were only attached translations of the actual official letter which was in Malay. Thus HM's anger might have been more than just a letter, perhaps an accumulation of various earlier annoyances. Besides, his show of royal indignation on such an issue does not match his normal character.

The two questions I have are:

(a) much as Guan Eng's earlier example has set a bad precedence for Chinese translation to normally official Bahasa letters or notice, is that prohibited?

At that time PM Mahathir brushed Guan Eng's faux pas aside, saying, “It’s a minor mistake, I don’t want to make it an issue. Sometimes we make mistakes."

"I think he issued it in three languages, but for the Chinese audience he issued a statement in Chinese, that’s all.”

“We are not going to advise [Guan Eng]. He made a mistake, not intentional. He can issue a statement where he is empowered. When the announcement should be made by him, and that’s what he has done”.

So it was an administrative mistake by Guan Eng though not an earth-shaking one, unless someone like Khaled Nordin wanted to make a Bahasa mountain out of a Chinese molehill.

Thus, for Chan Wei Kjhan (Johor councillor for Zon 8 Taman Bukit Indah) to repeat a mistake was not a bright idea. But then we need to ask: is it prohibited?

(b) HM Sultan Johor is a constitutional monarchy of his state, so really, should he be involved in such an agitated state on a trivial administrative-political matter?

As we heard from Thomas Macaulay: A constitutional monarch is "A sovereign who reigns but does not rule".