diff --git a/engines/sci/engine/object.cpp b/engines/sci/engine/object.cpp
index 2fdbb9118f0..9dac479ba95 100644
--- a/engines/sci/engine/object.cpp
+++ b/engines/sci/engine/object.cpp
@@ -222,8 +222,7 @@ int Object::propertyOffsetToId(SegManager *segMan, int propertyOffset) const {
 	int selectors = getVarCount();
 
 	if (propertyOffset < 0 || (propertyOffset >> 1) >= selectors) {
-		error("Applied propertyOffsetToId to invalid property offset %x (property #%d not in [0..%d])",
-		          propertyOffset, propertyOffset >> 1, selectors - 1);
+		// Scripts contain instructions with invalid properties
 		return -1;
 	}
 
diff --git a/engines/sci/engine/scriptdebug.cpp b/engines/sci/engine/scriptdebug.cpp
index 16d1edb7cc7..e4ec0a88c23 100644
--- a/engines/sci/engine/scriptdebug.cpp
+++ b/engines/sci/engine/scriptdebug.cpp
@@ -316,8 +316,12 @@ reg_t disassemble(EngineState *s, reg_t pos, const Object *obj, bool printBWTag,
 			} else {
 				if (getSciVersion() == SCI_VERSION_3)
 					debugN("\t(%s)", g_sci->getKernel()->getSelectorName(param_value).c_str());
-				else
-					debugN("\t(%s)", g_sci->getKernel()->getSelectorName(obj->propertyOffsetToId(s->_segMan, param_value)).c_str());
+				else {
+					int propertySelector = obj->propertyOffsetToId(s->_segMan, param_value);
+					if (propertySelector != -1) {
+						debugN("\t(%s)", g_sci->getKernel()->getSelectorName(propertySelector).c_str());
+					}
+				}
 			}
 		}
 	}