diff --git a/internal/plugin/grpc_provider.go b/internal/plugin/grpc_provider.go
index ed32abc0a0..fdd203665b 100644
--- a/internal/plugin/grpc_provider.go
+++ b/internal/plugin/grpc_provider.go
@@ -483,7 +483,12 @@ func (p *GRPCProvider) PlanResourceChange(r providers.PlanResourceChangeRequest)
 	}
 
 	if metaSchema.Block != nil {
-		metaMP, err := msgpack.Marshal(r.ProviderMeta, metaSchema.Block.ImpliedType())
+		metaTy := metaSchema.Block.ImpliedType()
+		metaVal := r.ProviderMeta
+		if metaVal == cty.NilVal {
+			metaVal = cty.NullVal(metaTy)
+		}
+		metaMP, err := msgpack.Marshal(metaVal, metaTy)
 		if err != nil {
 			resp.Diagnostics = resp.Diagnostics.Append(err)
 			return resp
@@ -558,7 +563,12 @@ func (p *GRPCProvider) ApplyResourceChange(r providers.ApplyResourceChangeReques
 	}
 
 	if metaSchema.Block != nil {
-		metaMP, err := msgpack.Marshal(r.ProviderMeta, metaSchema.Block.ImpliedType())
+		metaTy := metaSchema.Block.ImpliedType()
+		metaVal := r.ProviderMeta
+		if metaVal == cty.NilVal {
+			metaVal = cty.NullVal(metaTy)
+		}
+		metaMP, err := msgpack.Marshal(metaVal, metaTy)
 		if err != nil {
 			resp.Diagnostics = resp.Diagnostics.Append(err)
 			return resp
diff --git a/internal/plugin6/grpc_provider.go b/internal/plugin6/grpc_provider.go
index 5fbdd8d4f9..02a48b694f 100644
--- a/internal/plugin6/grpc_provider.go
+++ b/internal/plugin6/grpc_provider.go
@@ -472,7 +472,12 @@ func (p *GRPCProvider) PlanResourceChange(r providers.PlanResourceChangeRequest)
 	}
 
 	if metaSchema.Block != nil {
-		metaMP, err := msgpack.Marshal(r.ProviderMeta, metaSchema.Block.ImpliedType())
+		metaTy := metaSchema.Block.ImpliedType()
+		metaVal := r.ProviderMeta
+		if metaVal == cty.NilVal {
+			metaVal = cty.NullVal(metaTy)
+		}
+		metaMP, err := msgpack.Marshal(metaVal, metaTy)
 		if err != nil {
 			resp.Diagnostics = resp.Diagnostics.Append(err)
 			return resp
@@ -547,7 +552,12 @@ func (p *GRPCProvider) ApplyResourceChange(r providers.ApplyResourceChangeReques
 	}
 
 	if metaSchema.Block != nil {
-		metaMP, err := msgpack.Marshal(r.ProviderMeta, metaSchema.Block.ImpliedType())
+		metaTy := metaSchema.Block.ImpliedType()
+		metaVal := r.ProviderMeta
+		if metaVal == cty.NilVal {
+			metaVal = cty.NullVal(metaTy)
+		}
+		metaMP, err := msgpack.Marshal(metaVal, metaTy)
 		if err != nil {
 			resp.Diagnostics = resp.Diagnostics.Append(err)
 			return resp
diff --git a/internal/terraform/node_resource_plan_partialexp.go b/internal/terraform/node_resource_plan_partialexp.go
index 3851f14757..73b0d3f54e 100644
--- a/internal/terraform/node_resource_plan_partialexp.go
+++ b/internal/terraform/node_resource_plan_partialexp.go
@@ -210,6 +210,10 @@ func (n *nodePlannablePartialExpandedResource) managedResourceExecute(ctx EvalCo
 		Config:           unmarkedConfigVal,
 		PriorState:       priorVal,
 		ProposedNewState: proposedNewVal,
+		// TODO: Should we send "ProviderMeta" here? We don't have the
+		// necessary data for that wired through here right now, but
+		// we might need to do that before stabilizing support for unknown
+		// resource instance expansion.
 	})
 	diags = diags.Append(resp.Diagnostics.InConfigBody(n.config.Config, n.addr.String()))
 	if diags.HasErrors() {