Bells only apply the glowing affect to raid mobs within 48 blocks, despite the 1.14.2 Pre-release blog post saying "Increased search radius for bell when starting a raid from 48 to 64 blocks". This was tested in both 1.14.2-pre1 and 1.14.2.

To reproduce

• Place a bell (e.g. at x=0, z=0)
• Summon NoAI raid mobs within 32, 48 and 64 blocks, e.g. with the following command:

  /summon vindicator ~ ~ ~ {NoAI:1b,PersistenceRequired:1b}
  

• Ring the bell

Mobs farther than 48 blocks but closer than 64 blocks will not receive the Glowing effect. In the attached screenshot (2019-05-31_15.54.13.png), the iron blocks represent a distance of 10 blocks.