AlloyDB 2000 row alter table typeORM sync taking > 1min

Question

We have a freshly minted Postgres DB running on AlloyDB. When deploying new code the DB seems to hang. It is getting worse. There are only 2000 rows in the table, but when I check the query insights there is an ALTER TABLE payments query taking minutes. There is also what I assume is a typeORM table scan happening which is also hanging. You can see that only one column has a foreign key and it's on a primary key. You can also see that the query is being called multiple times per day as we've only had the system in place 8 weeks and we have less than 100 deployments. I'm not sure why it would get called without a change in schema. Two other tables are also listed similarly and have near-zero execution time including the purchases table.

import { Column, Entity, PrimaryGeneratedColumn, CreateDateColumn, UpdateDateColumn, ManyToOne, JoinColumn } from 'typeorm';
import { Purchase } from './purchase.entity';

@Entity('payments')
export class Payment {
  @PrimaryGeneratedColumn({
    type: 'bigint',
    name: 'id',
  })
  id: number;

  @Column({
    nullable: false,
    type: 'bigint'
  })
  purchase_id: number;
  
  @ManyToOne(() => Purchase, purchase => purchase.payments, { lazy: true })
  @JoinColumn({ name: 'purchase_id' })
  purchase: Promise<Purchase>;

  @Column({
    name: 'payment_date',
    type: 'date',
    nullable: false,
    default: new Date(),
  })
  payment_date: Date;

  @Column({
    nullable: false,
    default: 0
  })
  payment_amount: number;

  @Column({
    type: 'varchar',
    default: "pending"
  })
  attempts: string;

  @Column({
    type: 'varchar',
    nullable: true
  })
  payment_intent_id: string;

  @Column({
    name: 'last_attempted_date',
    type: 'date',
    nullable: true,
    default: null,
  })
  last_attempted_date : Date;

  
  @Column({
    type: 'varchar',
    nullable: true
  })
  error_response: string;

  @CreateDateColumn()
  created_at: Date;

  @UpdateDateColumn()
  updated_at: Date;
}