It isn’t true. Text capture doesn’t work on a “how close you are to spawn” basis but on the user interaction basis.
That can be mitigated if you have people actively playing your game. The more users play it, the more text will be captured.
Overall, it takes on average 2 minutes for the system to capture the text that users see and put it in the table. I recommend reading The Introduction to Localization post on the DevHub if you have any issues.
I find this strange, because on my game that sometimes reaches 10,000 concurrent players, it takes several days for one string of text to be captured, but when I just rejoin over and over, it finally works. Maybe its a bug on my end.