Why doesn't vsftpd work with ssl on Ubuntu 20.04?

Question

linux

Good afternoon.
Installed and configured vsftpd on Ubuntu 20.04 ( according to the article ), everything works without configuring ssl, problems start when ssl is enabled:

1. PhpStorm IDE cannot load some files with the message:

Could not put FTP file.
At the same time vsftpd logs (after debug_ssl=YES) :

Mon Oct  5 13:15:16 2020 [pid 534346] [user] DEBUG: Client "::ffff:X", "SSL version: TLSv1.3, SSL cipher: TLS_AES_128_GCM_SHA256, not reused, no cert"
Mon Oct  5 13:15:16 2020 [pid 534346] [user] DEBUG: Client "::ffff:X", "SSL shutdown state is: NONE"
Mon Oct  5 13:15:16 2020 [pid 534346] [user] DEBUG: Client "::ffff:X", "SSL shutdown state is: SSL_SENT_SHUTDOWN"
Mon Oct  5 13:15:16 2020 [pid 534346] [user] DEBUG: Client "::ffff:X", "SSL shutdown state is: 3"
Mon Oct  5 13:15:16 2020 [pid 534347] [user] OK DOWNLOAD: Client "::ffff:X", "/Path/blog.min.js", 49152 bytes, 104.76Kbyte/sec
Mon Oct  5 13:15:18 2020 [pid 534346] [user] DEBUG: Client "::ffff:X", "SSL version: TLSv1.3, SSL cipher: TLS_AES_128_GCM_SHA256, not reused, no cert"
Mon Oct  5 13:15:18 2020 [pid 534346] [user] DEBUG: Client "::ffff:X", "SSL shutdown state is: NONE"
Mon Oct  5 13:15:18 2020 [pid 534346] [user] DEBUG: Client "::ffff:X", "SSL shutdown state is: SSL_SENT_SHUTDOWN"
Mon Oct  5 13:15:18 2020 [pid 534346] [user] DEBUG: Client "::ffff:X", "SSL ret: 18446744073709551615, SSL error: error:00000000:lib(0):func(0):reason(0), errno: 32"
Mon Oct  5 13:15:18 2020 [pid 534347] [user] FAIL UPLOAD: Client "::ffff:X", "/Path/blog.min.js", 57344 bytes, 170.36Kbyte/sec

2. FileZilla downloads files that PhpStorm has problems with, but when disconnected from the server, the following:

GnuTLS error -15 in gnutls_record_recv: An unexpected TLS packet was received.
Error:	Could not read from socket: ECONNABORTED - Connection aborted
Error:	Disconnected from server

For the test, I did the same installation on Ubuntu 16.04 and everything worked.
Who faced, tell me how to find / fix.

UPD: I tried to use a certificate from Let's Encrypt instead of a self-signed one, but the problem persisted. Interestingly, the problem recurs most often on the same files and occurs during transfer at the same size (at the same time, these files are uploaded correctly through FileZilla and even if the files are deleted, the problem repeats)