diff --git a/src/project.cpp b/src/project.cpp
index 3370dacd..475512ff 100644
--- a/src/project.cpp
+++ b/src/project.cpp
@@ -1977,18 +1977,29 @@ bool Project::readFieldmapMasks() {
     projectConfig.setSaveDisabled(true);
 
     // Read Block masks
-    auto it = defines.find(metatileIdMaskName);
-    if (it != defines.end())
-        projectConfig.setBlockMetatileIdMask(static_cast<uint16_t>(it.value()));
-    it = defines.find(collisionMaskName);
-    if (it != defines.end())
-        projectConfig.setBlockCollisionMask(static_cast<uint16_t>(it.value()));
-    it = defines.find(elevationMaskName);
-    if (it != defines.end())
-        projectConfig.setBlockElevationMask(static_cast<uint16_t>(it.value()));
+    auto readBlockMask = [defines](const QString name, uint16_t *value) {
+        auto it = defines.find(name);
+        if (it == defines.end())
+            return false;
+        *value = static_cast<uint16_t>(it.value());
+        if (*value != it.value()){
+            logWarn(QString("Value for %1 truncated from '0x%2' to '0x%3'")
+                .arg(name)
+                .arg(QString::number(it.value(), 16).toUpper())
+                .arg(QString::number(*value, 16).toUpper()));
+        }
+        return true;
+    };
+    uint16_t blockMask;
+    if (readBlockMask(metatileIdMaskName, &blockMask))
+        projectConfig.setBlockMetatileIdMask(blockMask);
+    if (readBlockMask(collisionMaskName, &blockMask))
+        projectConfig.setBlockCollisionMask(blockMask);
+    if (readBlockMask(elevationMaskName, &blockMask))
+        projectConfig.setBlockElevationMask(blockMask);
 
     // Read RSE metatile attribute masks
-    it = defines.find(behaviorMaskName);
+    auto it = defines.find(behaviorMaskName);
     if (it != defines.end())
         projectConfig.setMetatileBehaviorMask(static_cast<uint32_t>(it.value()));
     it = defines.find(layerTypeMaskName);