You encrypt the data ABCD -> EDGF.
You encrypt the data DEFG -> HGJI
Someone intercepts the data, and has: EDGF and HGJI
And now?
Or maybe like this: Since OTP and data are interchangeable, due to matching lengths, isn't using the same OTP with different data, essentially the same like using the same data with a different key?
Story time: The USSR once reused an OTP key (after years or even decades, can't recall), but a US' three letter agency had the old ciphertext (A') and reused that to break the new ciphertext (B'). They probably had some scheme with a broadcaster saying "use codebook 1234, the secret is GARBLED DATA". At least that's the story a cryptography lecturer told us (and the fragments I remember).
I guess one thing to note is that, if what you were transmitting was just random noise to begin with, OTP re-use may not matter/be evident. But essentially all data that people care about transmitting isn't random noise, it has some structure, and that structure comes through with OTP re-use (more and more the more you re-use and the more data you re-use with).
AIUI, the Enigma machine (not quite an OTP but I think similar) was broken in part because of just a few key re-uses https://en.wikipedia.org/wiki/Cryptanalysis_of_the_Enigma#Op...
From my limited knowledge of the matter, that alone doesn't give you the cypher - you'll need to know additional information about the messages to get the cypher (statistics of words, conditional probabilities of letter sequences etc.). But without the one reuse of your cypher, you couldn't apply these techniques.
That ASCII example is rather extreme, but all messages have patterns as long as you’re given enough of them you can break a reused OTP.