Shia shaykh ar-Rawwad in his treatise “ar-Risala fi khabarul daif” (p42) quoted their master muhadith Abbas Qummi:
“and they don’t understand that IF chain (of report) is authentic that going to be a proof upon slaves, because report of truthful is a proof, and IF NOT AUTHENTIC, then IT IS NOT permitted to reject it due to possibility of coming from Ahlalbayt, and that would become a objection to them, as it comes in honourable report..”
1) Abbas Qummi apparently has no clue about terms of sound report in accordance to shiaizm. Or he used one from the “hundreds” available. Because if all reporters of hadith were thiqat (truthful) in accordance to shias is not enough for hadith to be sound (hujjah).
2) Here we have good example from known shia muhadith, that in reality THEY DON’T CARE about chain being sound or not, because even if it is not, they still shouldn’t reject it. It is good explanation of attitude which we can see from majority of modern shias. If hadith suits to their beliefs, they absolutely don’t care if chain of transmission is sound or not.
As a proof for our point of view, that shias has no right to reject any ahadeth, I’d like to cite a hadith from their book “Basair ad-Darajat”:
from Abu Abdullah (alaihi salam): Don’t reject ahadeth which someone brought to you, because you don’t know, may be they are truth, (and by rejecting them) you would reject Allah beyond his Throne.