There's no such thing as a lengthy I-94, each one pertains to one admission. The lookup will only show your most recent I-94. You may be confusing this with the travel history lookup, those are two different things. In any case, you should be seeing results from both, especially if it worked previously with the same passport number.
Since you mentioned you are not actually in the US, I have seen reports of lookup issues related to browser time zones, you can try adding or subtracting one day to your DOB and see if that makes any difference for you.