citrus-http:server plaintext validator succeeds in v2.7.2 but fails in v2.7.8

**Citrus Version**
2.7.8

**Expected behavior**
I'm upgrading from 2.7.2 to 2.7.8. A test case containing the action below succeeds in 2.7.2 but fails in 2.7.8.
I would expected that it also succeeds in 2.7.8.
May I ask you for any hint for a fix?

Thanks & Regards,

Binh

**Actual behavior**
Test case failed with following exception:
```
com.consol.citrus.exceptions.TestCaseFailedException: Text values not equal, expected 'email_addr=Max.Mustermann%40gmail.com&extref=vDqGHtBt&last_name=Mustermann&first_name=Max' but was '{email_addr=[Max.Mustermann@gmail.com], extref=[vDqGHtBt], last_name=[Mustermann], first_name=[Max]}'
```

**Test case sample**
Action from test case:
```

```