Blizzard is aware of a bug that caused Level 21 glyphs to drop to 19 and level 15 glyphs to 14 after Patch 1.2.3 went live. A hotfix will be released later today to fix the issue.
With the release of Patch 1.2.3, players on the official forums have been reporting a reduction in their glyph XP.
Glyph XP Issues After Patch 1.2.3
The team has identified an issue that players are experiencing with paragon glyphs showcasing misrepresented levels from the levels achieved prior to the 1.2.3 update. We plan on addressing this on PC with a new client update that will be shipping later today. We will update players on timing of this release once available.
For console users, we plan on releasing an update with Xbox and PlayStation as soon as it becomes available. We will have updated timing later today.
Users that were max level on paragon glyph XP, you can re-level the glyphs in the meantime if you prefer until the fix is available. For those that were below the max glyph XP, you can still progress your glyphs and after the fix will have that glyph XP added to the old amounts prior to the 1.2.3 update.
Separately, we have seen reports from players regarding the advanced tooltip on the Tears of Blood glyph mentioning it is additive as opposed to multiplicative. This is a known issue that we noted on Friday.
This issue requires a client update and will also be addressed in the above fix once that patch becomes available.
We apologize for the issue and the inconvenience. The team is working on this as quickly as possible.
You can read the entire official news post HERE