Cannot assign to read only property 'writeQueueSize' of object '#<TCP>'

[vineet-suri]

Issue type:

[x ] question
[x ] bug report
[ ] feature request
[ ] documentation issue

Database system/driver:

[ ] cordova
[ ] mongodb
[ ] mssql
[ ] mysql / mariadb
[ ] oracle
[ x] postgres
[ ] cockroachdb
[ ] sqlite
[ ] sqljs
[ ] react-native
[ ] expo

TypeORM version:

[ x] latest
[ ] @next
[ ] 0.x.x (or put your version here)

Steps to reproduce or a small repository showing the problem:

1. Create an entity: AuditLog

@Entity('audit_log')
export class AuditLog extends BaseEntity {
    @PrimaryGeneratedColumn()
    id: number;

    @Column()
    ip: string;

    @Column({ type: 'varchar' })
    url: string;

    @Column({ name: 'method_name', type: 'varchar' })
    methodName?: string;

    @Column({ name: 'user_agent', type: 'varchar' })
    userAgent?: string;

    @Column({ name: 'status_code', type: 'varchar', length: 100 })
    statusCode: string;

    @Column({ name: 'err_msg', type: 'varchar', length: 100 })
    errMsg?: string;

    @Column({ name: 'err_trace', type: 'varchar', length: 100 })
    errTrace?: string;

    @Column({ name: 'req_body', type: 'json' })
    reqBody?: JSON;

    @Column({ type: 'json' })
    request: JSON;

    @Column({ type: 'json' })
    response: JSON;

    @Column({ name: 'response_time' })
    responseTime: string;

    @ManyToOne(type => User)
    user?: User;
}

2. Save entity in database using repository method, like this

async createLog(log: AuditLog): Promise<AuditLog> {
        const result = await this.auditLogRepo.save(log);
        return result;
    }

NestJs Interceptor makes call to this service method.
but the save method errors out with this stack trace:

(node:2037) UnhandledPromiseRejectionWarning: TypeError: Cannot assign to read only property 'writeQueueSize' of object '#<TCP>'
    at Function.assign (<anonymous>)
    at Function.OrmUtils.mergeDeep (/home/vineet/Haskell project/haskell_api/node_modules/typeorm/util/OrmUtils.js:89:28)
    at Function.OrmUtils.mergeDeep (/home/vineet/Haskell project/haskell_api/node_modules/typeorm/util/OrmUtils.js:86:26)
    at Function.OrmUtils.mergeDeep (/home/vineet/Haskell project/haskell_api/node_modules/typeorm/util/OrmUtils.js:86:26)
    at Function.OrmUtils.mergeDeep (/home/vineet/Haskell project/haskell_api/node_modules/typeorm/util/OrmUtils.js:86:26)
    at /home/vineet/Haskell project/haskell_api/node_modules/typeorm/persistence/Subject.js:210:33
    at Array.reduce (<anonymous>)
    at Subject.createValueSetAndPopChangeMap (/home/vineet/Haskell project/haskell_api/node_modules/typeorm/persistence/Subject.js:167:41)
    at /home/vineet/Haskell project/haskell_api/node_modules/typeorm/persistence/SubjectExecutor.js:270:85
    at Array.forEach (<anonymous>)
(node:2037) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 2)
(node:2037) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

Please help about why this is going wrong?