Seems that war declaration means canceling rights and power of Central Bank in the coutry that declared war.

At least in Russian laws, the power to govern all country finances and reserves goes to wartime administration and Central Bank powers become obsolete.

I didn't check all other countries laws yet, but I suppose they are not very different in the financial part. If you are interested in that rabbit hole - check that thing in the laws of your country. It could be interesting.

If you have examples that disprove that theory, you are welcome too.