The relevant word is דכא which in some scrolls is written דכה. See Deuteronomy 23:2.
While the portion of Aleppo Codex containing that word is currently lost, we do have the Aleppo Codex to Tehillim 90:3 where the same word appears spelled with an Alef. The Mesorah there notes that this spelling is used in three places and lists them: Deuteronomy 23:2, Tehillim 90:3 and Isaiah 57:15.
Many Ashkenazi scrolls used the Hey spelling, but upon seeing manuscript evidence some have started changing back to Alef (eg. the first Lubavitcher Rebbe). In the last 75 years when we have gained access to the Aleppo codex it seems the Alef side is even better supported.
See here for more discussion of the manuscript evidence in both directions.
See here for more variants in modern Torah scrolls.