Could @Chanku explain specifically what the issue is with shall in the legal sense?
I've mentioned this before, but shall itself has many different meanings, which in a legal sense all are slightly different. As such the use of 'shall' is sometimes used to mean something mandatory or something non-mandatory ("must" vs "can"/"may"). Lawsuits over the meaning of the word "shall" in a contract or law also occur with some frequency. As such it's better to avoid the use of 'shall', especially in legal documents. In Wintreath "shall" is used both in a "must" way and in a "can"/"may" way for example:
2.6 The Monarch, or any subordinate official appointed by the Monarch, shall have the authority to grant or deny citizenship to any person who applies.
The use of "shall" in this section clearly means, "has the duty/authority to" and not "must have the authority to". Meanwhile in the Fundamental Laws there is this phrase:
7. All legislation shall be initially introduced only in the Underhusen.
"Shall" in this sentence is being used to mean, "must" however it can be read as, "may" as well, especially since "shall" is used in this way elsewhere in the document (and even the same article, such as Article I, Section 16)
16. The Storting shall have the authority to issue advisory opinions on matters of constitutionality and legality to anyone whom the Storting has determined has standing to seek an advisory opinion.
"Shall" this sentence means "may" in a way, in that it has the authority to do this.
There is even a section that uses "shall" in both of these ways, which is Article I, Section 6
6. The Monarch shall announce his or her appointments and reappointments to the Overhusen at the conclusion of elections for the Underhusen. The Monarch shall at the same time also appoint a Chairperson of the Overhusen, who shall execute the procedural rules established by the Overhusen. In the event of a vacancy, the Monarch shall have the authority to appoint a new Peer to fill the vacancy.
The first use of "shall" is more-so like the usage of "must" or "will", the next use of "shall" is similar as well, in addition to the third use. The final use however is not the same, it can say the monarch "must" fill the vacancy, but instead it reads more like the monarch CAN fill the vacancy, if they so chose, but they do have the authority to appoint one.
As such, it just becomes confusing and in Wintrean Law it's been used like in RL law, which is not that good, so "shall" has become a problematic word for legal usage, for more information you can read
This Plain Language document from the US government suggesting to avoid the use of shall in legal documents