`grobner_basis(deg_bound=2)` error related to an open problem

[Georgi Guninski]

Hi SageMath Inc developers,

First there is an open problem on mathoverflow at [1]:
Conjectured Somos-like closed form of recurrences with polynomial coefficients

I would like a proof if possible.

The answer of Max Alekseyev there links to code using Groebner basis
over QQ.

If I modify the attached code adding `.groebner_basis(deg_bound=2)`,
I get series of errors:

====
RuntimeError: error in Singular function call 'groebner':
overflow at t^20

error occurred in or before standard.lib::stdhilb line 291: `
intvec hi = hilb( Id[1],1,W );`
expected intvec-expression. type 'help intvec;'
leaving standard.lib::stdhilb (0)
leaving standard.lib::groebner (1128)
===

If I remove deg_bound=2, the code works.

Attached is the modified testcase.

[1]: https://mathoverflow.net/q/476226/12481