I just tried building core-updates after the upgrade to TeX Live 2020
(core-updates commit f72a125) and texlive-amscls failed with a slightly
different error coming from glibc, but still indicative of heap corruption:
“corrupted size vs. prev_size”

Full build output attached, and relevant snippet below:

```
This is LuaTeX, Version 1.12.0 (TeX Live 2020) 
 restricted system commands enabled.
(./amsdtx.ins (/gnu/store/6w056ryry98gw1h6hl1xnh725l7k5jg9-texlive-latex-base-54632/share/texmf-dist/tex/latex/base/docstrip.tex
Utility: `docstrip' 2.5g <2018/05/03>
English documentation    <2018/05/03>

**********************************************************
* This program converts documented macro-files into fast *
* loadable files by stripping off (nearly) all comments! *
**********************************************************

********************************************************
* No Configuration file found, using default settings. *
********************************************************

)

Generating file(s) amsdtx.cls amsldoc.cls 

Processing file amsdtx.dtx (amsdtx) -> amsdtx.cls
                           (amsldoc) -> amsldoc.cls
File amsdtx.dtx ended by \endinput.
Lines  processed: 1196
Comments removed: 573 
Comments  passed: 1
Codelines passed: 584 

)
warning  (pdf backend): no pages of output.
Transcript written on amsdtx.log.
corrupted size vs. prev_size
error: in phase 'build': uncaught exception:
%exception #<&invoke-error program: "luatex" arguments: ("-interaction=nonstopmode" "-output-directory=build" "&luatex" "amsdtx.ins") exit-status: #f term-signal: 6 stop-signal: #f> 
phase `build' failed after 6.5 seconds
command "luatex" "-interaction=nonstopmode" "-output-directory=build" "&luatex" "amsdtx.ins" failed with signal 6
```

I’ll keep trying to run valgrind on it to see where the corruption happens.
-- 
Thanks,
Thiago