So I am trying to find an explanation as to why this is happening. I noticed that there is even a bug report about this from months ago, which received no attention at all — 164240 – Exported PDF doesn't take "Spacing to Borders" into account properly
Misaligned_plus_test.odg (10.8 KB)
As you can see, after you export the document as pdf, the plus sign goes off center for some reason. I tried to check every setting and I still cannot understand why this is happening.