As Jason Bassford and Michael Harvey mention, the time frame of one part of a sentence does not have to be the same as the time frame of another part of the sentence. This is particularly true when talking about reported speech or events. The event can be at any time, and the report about the event can be at any time. For example:
I hear/heard your party was a big success.
Did I hear the report on the party just now? Or did I hear about it in the past? Both make sense, depending on what you want to say.
This can also be true for current or future events:
I saw (in the past) that the big convention downtown has (currently) so many people trying to get in that they have (ongoing) to turn them away.
I see (just now) that the President will make (in the future) a speech in New York tomorrow afternoon.
Not all combinations will make sense, of course. The point is that the two parts of the sentence have independent time frames.