There has always been controversy surrounding the authenticity of the Dasam granth, and there always will be, I can't foresee it being resolved.
I'm no scholar and have not studied it in any real depth. However I am aware that there were many dozens of poets at the time that started to pen poetry in the same style as Guru Gobind Singh and this is where the authenticity questions started to arise and have continued ever since.
The significance of factors like Hemkunt sahib which stems from the bachitar natak composition ( the temple is claimed to be where the guru worshipped and united with God in his previous life, for those not aware) is always going to raise doubts.
My personal opinion is why did not any other Guru's mention previous lives.
There are many questionable discrepencies-you could say. The hindu influence and use of hindu mythology as Harsimritkaur ji mentions, especially referral to gods and goddesses which seems contradictory to One God in the Guru granth sahib, sexual promiscuity, degradation of women and use of intoxicants.
Like I say, i'm no scholar but this information I have gathered from numerous sources.
I remember coming across somewhere that the british were claimed to be responsible as there was literature found in a british library with very similar translations to some Dasam granth contents! Not sure how true this is, but the british did try to bury sikhism and artifacts during the raj.
I feel that I shouldn't give such things due regard and concern as these issues convince me more and more everytime to uphold, honour, embrace, believe, hold to the highest order, live with and worship the one and true Guru Granth Sahib and that I am wasting my time looking elsewhere.
We shouldn't ever equate the Dasam granth to the Guru Granth Sahib and should never even try (by solving the controversial issues).
I know it contains some beautiful bani. but we should still treat it as sikh literature, learning from the contents that are in line with the rest of the Granth and sikh teachings.
BSCHEEMA JI....we are not even "finished" Mool mantar yet !!!..Just how many SIKHS are genuinely totally TRUTHFUL LIVING.....Satnamis.....just how many are NIRVAIR....NIRBHAU...i see many wearing red threads on their wrists (Scared/seeking protection..from evil eyes..black magic..bad luck..buree nazar..blah blah blah..)..I see so many Sikhs 24/7 bloo.dy mad at even the slightest "provcocation"...swords come out and turbans fly over goluck..gurdware elections..is that Nirvair ?? So we are mostly at Beginners level...and yet we claim we have Finished the entire Sri Guru Granth Sahib Ji and need "martial spirits" from a Chandi goddess with seven arms who rides a lion and drinks blood..wah wah wah...how utterly misguided moorakhs we are...a Famous Taksaal head found over 1500 "mistakes" in Sri Guru Granth Sahib Ji..and we take that lying down...the same taksaal that finds NONE "mistakes" in dg inspite of thousands of errors...
Harsimirit Ji,dasam granth means "10th granth". It does not mean "granth from the 10th". That is why I asked where is dooja granth teeja granth, etc.
And why is it that Guru Granth Sahib uses "mahala" like Mahala teeja, panjwa, etc., while dasam granth used "pathsahi dasveen"?
There are many idols mentioned from Budhism, as well, not the original Budhism, but from the Budhism that was changed due to Brahmanism in order to divide the people. There are so many sects of Budhism which is supposed to be a religion based on revealed truths, not based on poojarism and rituals. Emphasis is taken away from the wisdom that Sidhartha Gautama taught the people, and now the emphasis is on Sidharta himself. But pure Budhism teaches that we all can become a budha with the gian. This phrase "Budh" is mention numberous times in Guru Granth Sahib.
I do not see this type of Budh in dasam granth, but the brahmatic influence. We Sikhs are suffering the same fate as our Budhist neighbors. Buddhism does not believe in idols, and neither does Guru Granth Sahib. So why are so many Sikhs making idols out of the baba ji sants and neeshaan sahibi? They are making an idol out of Guru Granth Sahib, too, but not learning what Guru ji teaches.
I heard that there are 7 granths competing for guruship.