There's a one of patch for same bug...we had a TAR open with Oracle support and
they did had a fix to it
> Patch 4015165 (REGRN:SCALAR VARCHAR2 IN BINDS WITH
DIFFERENT SIZE RANDOMLY FAILS WITH ORA-06502
Quoting Mohammad Rafiq <rafiq9857@(protected)>:
> After a recent upgrade to 9206, hit the following bug introduced in 9206.
> Just for your info of those who are planning for upgrade. The patch
> set released for AIX, HP RISC 64 Linux x86 and Solaris 32 and 64 bit.
> Patchset for Windows being back ported. This is still not reported as
> known bug so far patchset update document.
> Bug 4015165 Unexpected ORA-6502
from PLSQL using host binds when using
> CHAR length semantics
> This note gives a brief overview of bug 4015165.
> Product (Component) PL/SQL (Plsql)
> Range of versions believed to be affected Versions >= 126.96.36.199 but < 10.2
> Versions confirmed as being affected
> * 188.8.131.52
> Platforms affected Generic (all / most platforms affected)
> It is believed to be a regression in default behaviour thus:
> * Regression introduced in 184.108.40.206