In 1.13.2, it was possible to trade with villagers to make them willing to breed with mobgrief false.  In 1.14 this was changed so they can only breed with food, hence it is impossible to breed villagers with mobgrief false.  This issue is present in the 1.14 full release and all versions between to the 1.14.4 full release.  I'm not sure which snapshot this was introduced in prior to the 1.14 full releases.

Steps to attempt to reproduce breeding in 1.13.2:

1) Obtain two villagers and trade to level them up to make them willing.

2) Add in enough doors for them to be able to breed.

3) Wait for them to breed.

Steps to attempt to reproduce breeding in 1.14+:

1) Obtain two villagers and trade to level them up to make them willing.  Note: this does not work anymore.

2) Add in enough beds for them to be able to breed.

3) Wait for them to breed.  Note: they do not breed.

The three following worlds are a default superflat world with three villagers levelled up once, and the blocks (beds for 1.14, doors for 1.13.2) that should make them breed.

Minecraft 1.13.2 breeding working: https://www.mediafire.com/file/g7e8vz3nuqajxm9/Villagers_willing_to_Breed.zip/file

Minecraft 1.14.0 breeding not working: https://www.mediafire.com/file/l7v46h508ihgwab/Villager_Unwilling_to_Breed.zip/file

Minecraft 1.14.4 breeding not working: https://www.mediafire.com/file/c3dcgdcteq7y9hh/Villager_Unwilling_to_Breed_%281.14.4%29.zip/file

Please do let me know if you need any other information and I'll do my best to provide it.