Have the same issue on PS 1.7.6.7 after upgrade. php 7.2.29
Selected Features for product are not saving.
Investigated DB and found out that the new "id_feature_value" is crated in table "_feature_value" also "custom" is set to "1" as all other rows has "0" value.
empty feature values are added to table "_feature_value_lang" with the same "id_feature_value",
This new "id_feature_value" is assigned to product in table "_feature_product".
Debug mode shows no errors.
Console shows some, see atachement.
Why it is happening so? How to fix?