They should not, as long as you create the A records as soon as you move to Cloudflare nameservers.
Your A records are the following:
#1
- Type “A”
- Name: www
- IPv4 address: The IP address in the client area
- TTL: Auto
- Proxy status: The orange cloud
#2
- Type “A”
- Name: yourdomain.tld
- IPv4 address: The IP address in the client area
- TTL: Auto
- Proxy status: The orange cloud
Thanks!