Is it true that al-Shaheed do not have a bad smell as those who died in a normal way?

Praise be to Allah, the Lord of the World; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

It is accurate and fixed that martyrs are alive finding their sustenance in the presence of their Lord, and they have been preferred and distinguished by Allah from the other believers in their enjoyment in the Jannah. So that is an advantage of the martyrs and a characteristic of their lives in the grave.
Regarding the issue that their corpses don't change, as far as we know there is no proof which indicates that. But concerning the martyr's body and his smell of musk, it is also fixed from the narrations but on Judgment Day. That fragrance of musk will be a manifestation of the Shahid's merit and his special mention amongst the creatures on that tremendous gathering on Judgment Day.
In Hadith which is reported by al-Bukhari and Muslim from Abu Hurairah (Radiya Allahu Anhu) that the Prophet (Sallallahu Alaihi wa Sallam) said: "Every wound which the Muslim gets it on the path of Allah (Jihad) will be in the same shape on the Resurrection as it was stabbed, the blood will flow. Its colour will be the colour of the blood and the fragrance will be fragrance of the musk" . [Reported by Imam Bukhari ].
And for this reason, the washing of the battle martyr is abandoned.
With this proof, the questioner and the others should know that disintegration of the Muslim bodies who were killed in Jenin camp by injustice - defending themselves, religion, possessions, honour and their land, doesn't prove that they are not martyrs. It is absolutely accurate with no doubt that whoever is killed while protecting his property, his life, his family and he is a Muslim, that person is a Shahid irrespective of the smell of his corpse changes or not. There is an authentic Hadith from the Prophet (Sallallahu Alaihi wa Sallam) who said: "Whoever is killed while protecting his property, then he is martyr; and whoever is killed while protecting his religion, then he is martyr; and whoever is killed while protecting his life, then he is martyr; and whoever is killed while protecting his family, then he is martyr" . [Reported by al-Tirmizi and there is a lot of other proofs].
Allah knows best.