The \t control code advances the cursor horizontal position to the next tab stop. However, it only does this when the cursor is not already at a tab stop. If the cursor is at a tab stop, the cursor position does not change. The expected behavior is for the cursor position to move to the next tab stop.

-- works as expected: prints x, advances to next tab stop, prints y
print("x\ty")

-- expected: indents by one tab stop, prints x
-- actual: cursor position does not change, prints x
print("\tx")

-- expected: prints x, advances two tab stops, prints y
-- actual: prints x, advances one tab stop, prints y
print("x\t\ty")

PICO-8 0.2.4b.

Nice one -- fixed for 0.2.4c.