I am in a situation where my current employer is filing the H1B amendment for change of location. There was already a H1B transfer petition filed by another new employer which is yet to receive the receipt. Will my current employer get to know that there is transfer petition in process? Is there any chance that either of these two petitions get rejected showing the other as reason?
No, your current employer will not know.
If you already have a visa allocated to you (from the cap lottery), then you can have multiple employers petitioning H1b for you (on the same visa allocation), but you only can work for one of them at a time. The "H1b transfer" petition is actually a new petition, just exempt from cap since you already have a visa allocated. Same with the location change petition.