Protobuf.js cannot parse fields with message values inside of custom field option messages

[murgatroid99]

protobuf.js version: 6.9.0

Protobuf.js fails to parse this .proto file, throwing this error:

Error: illegal name '}' (deps/envoy-api/envoy/api/v2/core/http_uri.proto, line 53)
    at illegal (/mnt/d/Documents/grpc-node/packages/grpc-js/node_modules/protobufjs/src/parse.js:94:16)
    at parseOptionValue (/mnt/d/Documents/grpc-node/packages/grpc-js/node_modules/protobufjs/src/parse.js:561:27)
    at parseOptionValue (/mnt/d/Documents/grpc-node/packages/grpc-js/node_modules/protobufjs/src/parse.js:564:21)
    at parseOption (/mnt/d/Documents/grpc-node/packages/grpc-js/node_modules/protobufjs/src/parse.js:553:9)
    at parseInlineOptions (/mnt/d/Documents/grpc-node/packages/grpc-js/node_modules/protobufjs/src/parse.js:587:17)
    at parseField_line (/mnt/d/Documents/grpc-node/packages/grpc-js/node_modules/protobufjs/src/parse.js:378:13)
    at ifBlock (/mnt/d/Documents/grpc-node/packages/grpc-js/node_modules/protobufjs/src/parse.js:292:17)
    at parseField (/mnt/d/Documents/grpc-node/packages/grpc-js/node_modules/protobufjs/src/parse.js:368:9)
    at parseType_block (/mnt/d/Documents/grpc-node/packages/grpc-js/node_modules/protobufjs/src/parse.js:340:21)
    at ifBlock (/mnt/d/Documents/grpc-node/packages/grpc-js/node_modules/protobufjs/src/parse.js:288:17)

referring to this field of the message:

  google.protobuf.Duration timeout = 3 [(validate.rules).duration = {
    required: true
    gte {} // This is the line the error refers to
  }];

The protoc tool parses this file just fine, so this is a valid protobuf definition.