diff --git a/internal/plans/objchange/objchange.go b/internal/plans/objchange/objchange.go
index f806174f0c..f21cd9b6b2 100644
--- a/internal/plans/objchange/objchange.go
+++ b/internal/plans/objchange/objchange.go
@@ -429,7 +429,7 @@ func optionalValueNotComputable(schema *configschema.Attribute, val cty.Value) b
 // values have been added. This function is only used to correlated
 // configuration with possible valid prior values within sets.
 func validPriorFromConfig(schema nestedSchema, prior, config cty.Value) bool {
-	if config.RawEquals(prior) {
+	if unrefinedValue(config).RawEquals(unrefinedValue(prior)) {
 		return true
 	}
 
@@ -446,7 +446,7 @@ func validPriorFromConfig(schema nestedSchema, prior, config cty.Value) bool {
 		}
 
 		// we don't need to know the schema if both are equal
-		if configV.RawEquals(priorV) {
+		if unrefinedValue(configV).RawEquals(unrefinedValue(priorV)) {
 			// we know they are equal, so no need to descend further
 			return false, nil
 		}
diff --git a/internal/plans/objchange/plan_valid.go b/internal/plans/objchange/plan_valid.go
index 6e8941fa02..ad7c051783 100644
--- a/internal/plans/objchange/plan_valid.go
+++ b/internal/plans/objchange/plan_valid.go
@@ -270,11 +270,11 @@ func assertPlannedAttrValid(name string, attrS *configschema.Attribute, priorSta
 func assertPlannedValueValid(attrS *configschema.Attribute, priorV, configV, plannedV cty.Value, path cty.Path) []error {
 
 	var errs []error
-	if plannedV.RawEquals(configV) {
+	if unrefinedValue(plannedV).RawEquals(unrefinedValue(configV)) {
 		// This is the easy path: provider didn't change anything at all.
 		return errs
 	}
-	if plannedV.RawEquals(priorV) && !priorV.IsNull() && !configV.IsNull() {
+	if unrefinedValue(plannedV).RawEquals(unrefinedValue(priorV)) && !priorV.IsNull() && !configV.IsNull() {
 		// Also pretty easy: there is a prior value and the provider has
 		// returned it unchanged. This indicates that configV and plannedV
 		// are functionally equivalent and so the provider wishes to disregard
@@ -463,3 +463,12 @@ func assertPlannedObjectValid(schema *configschema.Object, prior, config, planne
 
 	return errs
 }
+
+// unrefinedValue returns the given value with any unknown value refinements
+// stripped away, making it a basic unknown value with only a type constraint.
+func unrefinedValue(v cty.Value) cty.Value {
+	if !v.IsKnown() {
+		return cty.UnknownVal(v.Type())
+	}
+	return v
+}
diff --git a/internal/plans/objchange/plan_valid_test.go b/internal/plans/objchange/plan_valid_test.go
index 316bf56133..655c6e22f7 100644
--- a/internal/plans/objchange/plan_valid_test.go
+++ b/internal/plans/objchange/plan_valid_test.go
@@ -1796,11 +1796,39 @@ func TestAssertPlanValid(t *testing.T) {
 				)),
 			}),
 			[]string{
-				`.set: count in plan (cty.UnknownVal(cty.Number)) disagrees with count in config (cty.NumberIntVal(1))`,
-				`.list: count in plan (cty.UnknownVal(cty.Number)) disagrees with count in config (cty.NumberIntVal(1))`,
-				`.map: count in plan (cty.UnknownVal(cty.Number)) disagrees with count in config (cty.NumberIntVal(1))`,
+				`.set: count in plan (cty.UnknownVal(cty.Number).Refine().NotNull().NumberLowerBound(cty.NumberIntVal(0), true).NumberUpperBound(cty.NumberIntVal(9.223372036854775807e+18), true).NewValue()) disagrees with count in config (cty.NumberIntVal(1))`,
+				`.list: count in plan (cty.UnknownVal(cty.Number).Refine().NotNull().NumberLowerBound(cty.NumberIntVal(0), true).NumberUpperBound(cty.NumberIntVal(9.223372036854775807e+18), true).NewValue()) disagrees with count in config (cty.NumberIntVal(1))`,
+				`.map: count in plan (cty.UnknownVal(cty.Number).Refine().NotNull().NumberLowerBound(cty.NumberIntVal(0), true).NumberUpperBound(cty.NumberIntVal(9.223372036854775807e+18), true).NewValue()) disagrees with count in config (cty.NumberIntVal(1))`,
 			},
 		},
+
+		"refined unknown values can become less refined": {
+			// Providers often can't preserve refinements through the provider
+			// wire protocol: although we do have a defined serialization for
+			// it, most providers were written before there was any such
+			// thing as refinements, and in future there might be new
+			// refinements that even refinement-aware providers don't know
+			// how to preserve, so we allow them to get dropped here as
+			// a concession to backward-compatibility.
+			&configschema.Block{
+				Attributes: map[string]*configschema.Attribute{
+					"a": {
+						Type:     cty.String,
+						Required: true,
+					},
+				},
+			},
+			cty.ObjectVal(map[string]cty.Value{
+				"a": cty.StringVal("old"),
+			}),
+			cty.ObjectVal(map[string]cty.Value{
+				"a": cty.UnknownVal(cty.String).RefineNotNull(),
+			}),
+			cty.ObjectVal(map[string]cty.Value{
+				"a": cty.UnknownVal(cty.String),
+			}),
+			nil,
+		},
 	}
 
 	for name, test := range tests {