[GNC] Trial balance

[Fred Tydeman]

I have run a Transaction report (for all accounts) for just one day in the
past (to find all the transactions on that one day).  It found just one
transaction where I bought 600 yuan for 99.07 USD (at an ATM in china).
The grand totals in the report are 0 USD and 0 yuan.

That one transaction has four splits:
Receive column:
  Assets:...:$china 600
  Trading:cash US:ftexx 99.07 Fid. TE MM
Spend column:
  Assets:..:Fid. TE MM  99.07 Fed. TE MM
  Trading:CURRENCY:CNY  600

That transaction is the first one in $china.  There is no Equity Opening
Balance (which would be zero) for $china.

I then ran a Trial Balance report; again for just that one day and all
accounts.  The two totals at the bottom of the report do not match (differ
by 5.46).  If I change the date to 6 days earlier (again for just one day),
the two totals match.

By one day, I mean both Start date and Date of report are the same.

OS:  Fedora Linux 37
GnuCash: 4.13
Trading accounts are on.

Is Trial Balance supposed to work when there is a mixture of currencies?
Is Trial Balance supposed to work for just one day in the past?
Do all accounts need an Equity Opening Balance?