diff --git a/lib/fhir_models/bootstrap/json.rb b/lib/fhir_models/bootstrap/json.rb
index 5a07654e..d156b26a 100644
--- a/lib/fhir_models/bootstrap/json.rb
+++ b/lib/fhir_models/bootstrap/json.rb
@@ -18,7 +18,7 @@ def self.from_json(json, namespace = FHIR)
         klass = namespace.const_get(resource_type)
         resource = klass.new(hash)
       rescue => ex
-        FHIR.logger.error("Failed to deserialize JSON:\n#{ex.backtrace}")
+        FHIR.logger.debug("Failed to deserialize JSON:\n#{ex.backtrace}")
         FHIR.logger.debug("JSON:\n#{json}")
         resource = nil
       end
diff --git a/lib/fhir_models/bootstrap/model.rb b/lib/fhir_models/bootstrap/model.rb
index f69bf31e..ac6ac6c1 100644
--- a/lib/fhir_models/bootstrap/model.rb
+++ b/lib/fhir_models/bootstrap/model.rb
@@ -283,7 +283,7 @@ def primitive?(datatype, value)
     def check_binding_uri(uri, value)
       valid = false
       # Strip off the |4.0.0 or |4.0.1 or |2014-03-26 or similar from the ends of URLs
-      uri&.gsub!(/\|[A-Za-z0-9\.\-]*/, '')
+      uri = uri&.gsub(/\|[A-Za-z0-9\.\-]*/, '')
       valueset = fhir_definitions.get_codes(uri)
 
       if uri == 'http://hl7.org/fhir/ValueSet/mimetypes' || uri == 'http://www.rfc-editor.org/bcp/bcp13.txt'
diff --git a/lib/fhir_models/bootstrap/xml.rb b/lib/fhir_models/bootstrap/xml.rb
index 4c53289a..0237ed53 100644
--- a/lib/fhir_models/bootstrap/xml.rb
+++ b/lib/fhir_models/bootstrap/xml.rb
@@ -135,7 +135,7 @@ def self.from_xml(xml, namespace = FHIR)
         hash = xml_node_to_hash(doc.root, namespace, klass)
         resource = klass.new(hash)
       rescue => ex
-        FHIR.logger.error("Failed to deserialize XML:\n#{ex.backtrace}")
+        FHIR.logger.debug("Failed to deserialize XML:\n#{ex.backtrace}")
         FHIR.logger.debug("XML:\n#{xml}")
         resource = nil
       end
diff --git a/lib/fhir_models/fhirpath/evaluate.rb b/lib/fhir_models/fhirpath/evaluate.rb
index 1cc05d82..5263c863 100644
--- a/lib/fhir_models/fhirpath/evaluate.rb
+++ b/lib/fhir_models/fhirpath/evaluate.rb
@@ -19,8 +19,8 @@ def self.get(key, hash)
     return 'http://unitsofmeasure.org' if key == '%ucum'
     return 'http://snomed.info/sct' if key == '%sct'
     return 'http://loinc.org' if key == '%loinc'
-    return key.gsub!(/\A\'|\'\Z/, '') if key.start_with?("'") && key.end_with?("'")
-    key.gsub!(/\A"|"\Z/, '') # remove quotes around path if they exist
+    return key.gsub(/\A\'|\'\Z/, '') if key.start_with?("'") && key.end_with?("'")
+    key = key.gsub(/\A"|"\Z/, '') # remove quotes around path if they exist
     if hash.is_a?(Array)
       response = []
       hash.each do |e|