diff --git a/prism/src/parser/ast/Property.java b/prism/src/parser/ast/Property.java
index 4fec06c1..3c8275ba 100644
--- a/prism/src/parser/ast/Property.java
+++ b/prism/src/parser/ast/Property.java
@@ -205,17 +205,28 @@ public class Property extends ASTElement
 					} else {
 						constValToMatch = constValues.getValueOf(constName);
 					}
-					if (constValToMatch == null)
+					if (constValToMatch == null) {
 						match = false;
 					// Check doubles numerically
-					else if (constValToMatch instanceof Double)
-						match = PrismUtils.doublesAreEqual(((Double) constValToMatch).doubleValue(), DefinedConstant.parseDouble(constVal));
+					} else if (constValToMatch instanceof Double) {
+						try {
+							match = PrismUtils.doublesAreEqual(((Double) constValToMatch).doubleValue(), DefinedConstant.parseDouble(constVal));
+						} catch (NumberFormatException e) {
+							// we currently ignore malformed constants
+							match = false;
+						}
 					// if constant is exact rational number, compare exactly
-					else if (constValToMatch instanceof BigRational)
-						match = BigRational.from(constVal).equals(constValToMatch);
+					} else if (constValToMatch instanceof BigRational) {
+						try {
+							match = BigRational.from(constVal).equals(constValToMatch);
+						} catch (NumberFormatException e) {
+							// we currently ignore malformed constants
+							match = false;
+						}
 					// Otherwise just check for exact string match for now
-					else
+					} else {
 						match = constValToMatch.toString().equals(constVal);
+					}
 
 					// We need all constants to match
 					allMatch &= match;