You were lucky perhaps? Here's what Kodak says about using it with sheet film:
"Note: Kodak T-Max developer is not recommended for use with any sheet film. Occasionally dark, blotchy coating called dichroic fog will appear on the emulsion side of your film and can only be removed by vigorously washing the film by hand, which carries the risk of scratching the image. Because roll films don't use the same adhesive coatings as sheet films between the emulsion and the film base, dichroic fog is not a problem when T-Max developer is used with roll film."