Apologies.

Translating the pronoun "that" with the relative pronoun
go is a common mistake of translation programs - but I should have realised it can also be made by learning humans. My mistake, sorry. (Oddly enough running your phrase through Google produced "I understand that".

)
I think the phrase you got from CorkIrish.com means literally "it is understood to me that ..." which is more like "it seems to me that ..." or "I understand that ... " (or "I get the idea that ...") where "that" is a relative particle that introduces a phrase describing exactly how you understand the situation.
The complier of the dictionary at CorkIrish.com no doubt assumed that the reader would not leave
go hanging without completion.
For a positive sentence
go is followed by urú (eclipsis) on the dependent form of the verb:
Tuigtear dom go bhfuil sé ró-thinn chun an obair a dhéanamh. "It seems to me that he is too sick (to do the work." "It get the impression that he is too sick to do the work."
If the ensuing phrase is negative
go becomes
nach:
Tuigtear dom nach bhfuil sé sásta an obair a dhéanamh."It seems to me that he is not willing/happy to do the work." "It get the impression that he is not willing/happy to do the work."
Tuigim anois é ! "I understand it now" could also be translated "(Now) I get it !"
Hope this helps.