There is an issue occurring where Objects with Translucent Blend Mode Material Aren't Affected by Refraction. This affects any translucent material regardless of the translucent materials settings. This issue does not appear to be a regression
Versions Tested: Issue occurs in all versions tested
4.17.2 CL - 3658906
4.18.3 CL - 3832480
4.19p4 CL - 3873914
4.20.0 CL - 3879785
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-55270 in the post.