"export = { }" vs "let a = { }; export = a", causes discrepancy in import behavior

TypeScript Version: 3.9.5

Search Terms: I searched import related bug labels

Code

//module a
export = {
  name: 'zzxoto'
};

//module b
const EX = { name: 'zzxoto' };
export = EX;



//////////////////////////////////////////////////////////////////
//when importing a

//this gives error:
//This module can only be referenced with ECMAScript imports/exports by turning on the 'esModuleInterop' flag and referencing its default export.ts(2497)
import { name } from './a';

//this works
import A from './a';
A.name;
//////////////////////////////////////////////////////////////////



//////////////////////////////////////////////////////////////////
//when importing b

//this works
import { name } from './b';

//this works too
import B from './b';
B.name
//////////////////////////////////////////////////////////////////


//tsconfig.json
{
  "compilerOptions": {
    "target": "ES2019",
    "module": "commonjs",
    "strict": false,
    "strictNullChecks": true,
    "allowJs": false,    
    "esModuleInterop": true
  },
  "include": ["**/*.ts"]
}

Expected behavior:
There should be no descrepancy while import module a vs module b.

Actual behavior:
Described above.

使用报告中的模块 a 和 b，以及 TypeScript 3.9.5 和提供的 tsconfig.json，重现该差异。在 esModuleInterop 下比较命名导入和默认导入，然后验证等效的导出形式是否产生一致的导入行为。