Error in NVDA 2026.1.1 when reading uppercase letters

[MartheGjelstad]

I am using NVDA 2026.1.1 with the built in MathCAT. I updated NVDA from version 2025.3.3, where I had MathCAT as an add-on. This add-on is now disabled. I have replaced the libmathcat_py.pyd in the folder C:\Program Files\NVDA with your new build @NSoiffer .

Below are some MathML expressions and how they are spoken with NVDA. I experience the same errors for Norwegian and English, both in ClearSpeak and SimpleSpeak.

Error 1

MathML expression:

<math> <munderover> <mo>⋂</mo> <mrow><mi>i</mi><mo>=</mo><mn>1</mn> </mrow> <mn>10</mn> </munderover> <msub><mi>S</mi><mi>i</mi></msub> </math>

Speech output in NVDA:

the intersection from i is equal to 1 to 10 of <say-asinterpret-as='characters'>s</say-as> sub i

---

Error 2

MathML expression:

<math xmlns="http://www.w3.org/1998/Math/MathML"> <mmultiscripts> <mi>A</mi> <mi>m</mi> <mi>n</mi> <mrow></mrow> <mi>p</mi> <mprescripts/> <mi>q</mi> <mrow></mrow> <mi>s</mi> <mi>t</mi> </mmultiscripts> </math>

Speech output in NVDA:

<say-as interpret-as='characters'>a</say-as> with 2 prescripts pre sub q pre sub s and pre super t and with 2 postscripts sub m and super n super p

---

Error 3

MathML expression:

<math> <munder> <mo>∑</mo> <mi>S</mi> </munder> <mi>i</mi> </math>

Speech output from NVDA:

the sum over <say-as interpret-as='characters'>s</say-as> of i

---

Error 4

MathML expression:

<math> <msub> <mo>∑</mo> <mi>S</mi> </msub> <mi>i</mi> </math>

Speech output from NVDA

the sum over <say-as interpret-as='characters'>s</say-as> of i

---

Error 5

MathML expression:

<math> <munder> <mo>∏</mo> <mi>S</mi> </munder> <mi>i</mi> </math>

Speech output from NVDA:

the product over <say-as interpret-as='characters'>s</say-as> of i

---

Error 6

MathML expression:

<math> <munderover> <mo>⋂</mo> <mrow><mi>i</mi><mo>=</mo><mn>1</mn> </mrow> <mn>10</mn> </munderover> <msub><mi>S</mi><mi>i</mi></msub> </math>

Speech output from NVDA:

the intersection from i is equal to 1 to 10 of <say-as interpret-as='characters'>s</say-as> sub i

---

@TimArborealis and @AndersEkl , have you experienced this?
@NSoiffer , any thoughts on what the problem could be?

[MartheGjelstad]

See issue #578 for a suggestion on what might be causing the problem.

[NSoiffer]

The problem comes from something that I added for Microsoft to avoid an SSML injection attack. My fix was in the wrong spot and escaped way too much. I'm working on a proper fix.