Slowdown in service

appid: DECCC828-2720-F3EA-FFAD-586EEF9BD600
I made a batch of calls Backendless.UserService.register in loop
I used synchronous calls and I thought it won’t make big impact on backend
(calls from browser, logged with user who have “super” role).
After couple of hundreds such calls I started get errors
POST https://api.backendless.com/v1/users/register 400 (Bad Request) sendRequest error message - Custom business logic execution has been terminated because it did not complete in permitted time - 20 seconds
I have beforeRegister event with only two “console.log” commands. And my other custom events started receive same errors too.
So, where I pushed too hard, what resource did I depleted?

We are investigating this issue

I forgot to add:
these erros were received during something like 10 minutes, and after that all got back to normal, script executed like 20 same requests and received one error:
POST https://api.backendless.com/v1/users/register 400 (Bad Request)
error message - Model Descriptor not found (/var/lib/backendless/repo/deccc828-2720-f3ea-ffad-586eef9bd600/files/servercode/JS/v1/model.json)
and after that run fine rest of loop (about 30 calls)

An internal ticket (BKNDLSS-13352) has been created an assigned to developer