Not necessarily - often you would both need to die within 7 years for inheritance tax to become due. Basically gifting wouldn’t result in more tax being payable it would only reduce inheritance tax liability (in many cases).
I think if you as a couple gift £500k, it could be thought of as each of you gifting £250k.
My understanding:
Let’s say a couple jointly own a home worth £800k and have £700k in cash in a joint account and own nothing else - so £750k “each”. They jointly gift £600k to a child. After 4 years 1 parent dies.
The deceased passes their share of the home to their spouse without inheritance tax liability. The £50k share of the remaining £100k in cash, that too is left to the spouse so no inheritance tax due. The £300k they gifted is less than £325k so no Taper Relief but is less than their Nil Rate Band anyway so no inheritance tax due on it. However, it does use up £300k of their £325k allowance.
In effect they pass their unused allowances of £25k NRB+ £175k RNRB to their spouse (£200k).
After 2 further years parent 2 dies. Parent 2 had “inherited” £200k of allowance and have £500k of their own allowances to use if they leave their property to their child. The £300k they gifted is also below £325k so again no Taper Relief.
Their estate is valued at £800k home + £100k cash + £300k which as gifted = £1.2million, they have £700k of allowances to use leaving £500k on which inheritance tax is due (£150k) just as if the gift had never been made.
If parent 2 died 8 years after the gift then there would be no inheritance tax due.
https://www.gov.uk/inheritance-tax/gifts