diff --git a/integration/global-this/global-this.bin b/integration/global-this/global-this.bin
index 9e29a07b9..4d78dcf07 100644
Binary files a/integration/global-this/global-this.bin and b/integration/global-this/global-this.bin differ
diff --git a/integration/grpc-js-use-date-false/grpc-js-use-date-false.ts b/integration/grpc-js-use-date-false/grpc-js-use-date-false.ts
index 6191ec2fd..441ecbc3b 100644
--- a/integration/grpc-js-use-date-false/grpc-js-use-date-false.ts
+++ b/integration/grpc-js-use-date-false/grpc-js-use-date-false.ts
@@ -59,7 +59,7 @@ export const TimestampMessage = {
   toJSON(message: TimestampMessage): unknown {
     const obj: any = {};
     if (message.timestamp !== undefined) {
-      obj.timestamp = fromTimestamp(message.timestamp).toISOString();
+      obj.timestamp = message.timestamp;
     }
     return obj;
   },
@@ -156,12 +156,6 @@ function toTimestamp(date: Date): Timestamp {
   return { seconds, nanos };
 }
 
-function fromTimestamp(t: Timestamp): Date {
-  let millis = (t.seconds || 0) * 1_000;
-  millis += (t.nanos || 0) / 1_000_000;
-  return new globalThis.Date(millis);
-}
-
 function fromJsonTimestamp(o: any): Timestamp {
   if (o instanceof globalThis.Date) {
     return toTimestamp(o);
diff --git a/integration/use-date-false/metadata.ts b/integration/use-date-false/metadata.ts
index fd39acde6..614e33d5b 100644
--- a/integration/use-date-false/metadata.ts
+++ b/integration/use-date-false/metadata.ts
@@ -50,7 +50,7 @@ export const Metadata = {
   toJSON(message: Metadata): unknown {
     const obj: any = {};
     if (message.lastEdited !== undefined) {
-      obj.lastEdited = fromTimestamp(message.lastEdited).toISOString();
+      obj.lastEdited = message.lastEdited;
     }
     return obj;
   },
@@ -85,12 +85,6 @@ function toTimestamp(date: Date): Timestamp {
   return { seconds, nanos };
 }
 
-function fromTimestamp(t: Timestamp): Date {
-  let millis = (t.seconds || 0) * 1_000;
-  millis += (t.nanos || 0) / 1_000_000;
-  return new globalThis.Date(millis);
-}
-
 function fromJsonTimestamp(o: any): Timestamp {
   if (o instanceof globalThis.Date) {
     return toTimestamp(o);
diff --git a/integration/use-date-false/use-date-test.ts b/integration/use-date-false/use-date-test.ts
index e81c22ceb..c350b16e8 100644
--- a/integration/use-date-false/use-date-test.ts
+++ b/integration/use-date-false/use-date-test.ts
@@ -19,14 +19,23 @@ describe("useDate=false", () => {
     const json = Metadata.toJSON({ lastEdited: nov29 });
     expect(json).toMatchInlineSnapshot(`
       {
-        "lastEdited": "1973-11-29T21:33:09.234Z",
+        "lastEdited": {
+          "nanos": 234567890,
+          "seconds": 123456789,
+        },
       }
     `);
     expect(Metadata.fromJSON(json).lastEdited).toMatchInlineSnapshot(`
       {
-        "nanos": 234000000,
-        "seconds": 123456789.234,
+        "nanos": 234567890,
+        "seconds": 123456789,
       }
     `);
   });
+
+  it("doesn't lose precision in encoding/decoding", () => {
+    const d = Metadata.fromJSON(Metadata.toJSON({ lastEdited: nov29 }));
+    expect(d.lastEdited?.seconds).toStrictEqual(nov29.seconds);
+    expect(d.lastEdited?.nanos).toStrictEqual(nov29.nanos);
+  });
 });
diff --git a/protoc.Dockerfile b/protoc.Dockerfile
index 08812dd47..286b16f24 100644
--- a/protoc.Dockerfile
+++ b/protoc.Dockerfile
@@ -1,10 +1,9 @@
 # Docker image for protoc
-FROM node:17-alpine3.14
+FROM node:current-slim
 ARG PROTOC_VERSION="3.19.1"
 ARG ARCH="x86_64"
 
-RUN apk add bash
-RUN apk add gcompat
+RUN apt-get update --yes && apt-get install --yes unzip
 ADD "https://github.com/protocolbuffers/protobuf/releases/download/v$PROTOC_VERSION/protoc-$PROTOC_VERSION-linux-$ARCH.zip" protoc.zip
 RUN mkdir /usr/local/lib/protoc && unzip protoc.zip -d /usr/local/lib/protoc && rm protoc.zip
 RUN ln -s /usr/local/lib/protoc/bin/protoc /usr/local/bin/protoc
diff --git a/src/main.ts b/src/main.ts
index 9033b2806..f4e19183b 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -1979,7 +1979,7 @@ function generateToJson(
       } else if (isTimestamp(field) && options.useDate === DateOption.STRING) {
         return code`${from}`;
       } else if (isTimestamp(field) && options.useDate === DateOption.TIMESTAMP) {
-        return code`${utils.fromTimestamp}(${from}).toISOString()`;
+        return code`${from}`;
       } else if (isMapType(ctx, messageDesc, field)) {
         // For map types, drill-in and then admittedly re-hard-code our per-value-type logic
         const valueType = (typeMap.get(field.typeName)![2] as DescriptorProto).field[1];