diff --git a/lang/m2/comp/LLlex.c b/lang/m2/comp/LLlex.c
index 627513387..92f8cea3f 100644
--- a/lang/m2/comp/LLlex.c
+++ b/lang/m2/comp/LLlex.c
@@ -582,6 +582,7 @@ lexwarning(W_ORDINARY, "overflow in constant");
 				LoadChar(ch);
 				if (!(ch == '+' || ch == '-' || is_dig(ch)))
 					goto noscale;
+				UnloadChar(ch);
 			}
 			if (np < &buf[NUMSIZE]) *np++ = 'E';
 			LoadChar(ch);